OLDSMOBILE 350 V8

A Mercedes-Beater That Went Down in Flames

It’s not going over the top to say very few engines had more impact on the American light diesel market than the Oldsmobile 350 V8. Here’s how it all went down.

The 1970s is when carefree American motoring went fully into the toilet. Thanks to the Arab oil embargos, fuel economy became the motoring public’s fixation. At the same time, emissions regulations had brought the mighty American V8 to its knees and choked-down cars and trucks couldn’t chirp a tire while sucking way more fuel that was suddenly four times as expensive. A 55-mph national speed limit was the disgusting condiment on a fecal matter sandwich.

The auto industry struggled to meet the challenges and addressed the issues in many ways, including by looking at diesel power. Hey what’s not to like about 25-35 percent better economy on fuel that’s 10-15 percent cheaper? (Then, not now.) Unfortunately, the American auto industry didn’t have suitable automotive diesels in-house. Asian and European automotive diesels were highly developed but generally small four-cylinders for compact cars. Those played well over there but everyone knew America wasn’t quite ready to abandon full-size cars and trucks.

In an SAE white paper from February of 1978, Olds engineers said their diesel quest began in 1973. They started big by installing GMC’s 478ci V6 Toro-Flow diesel into a full-sized car. Since Opel in Germany was an arm of GM, they tested an Opel Rekord four-cylinder diesel in a mid-sized Olds. They also tried a Nissan SD33 six-cylinder diesel in a full-sized car.

The Toro-Flow was physically too big and emissions-dirty. The 2.1L Opel was too small for a mid-size and the 100hp, 165 lb-ft, 3.3L Nissan six was too small for a full-sized car. They didn’t have many other choices without downsizing their car line, so they decided to develop a new engine in-house. The stout, reliable, fits-in-existing-platforms Olds 350 cubic-inch V8 gasoline engine came to mind as an architectural pattern.

Suppress that sneer! To that point in history, basing a diesel on gas engine architecture had occurred many times, most often successfully, and it allowed a manufacturer to use similar tooling for both engines. Conversions generally demanded an IDI combustion chamber, since they deliver a slower and lower pressure rise on the firing event and the engine structure can be lighter. IDI science was well explored at that point but Olds soon learned none of the previously developed IDI combustion chambers were suitable. They tested 300 combustion chamber combinations over a three-month period before settling on a design.

When they installed test engines into cars, a pleasant surprise emerged. The goal had been to equal the performance of the Olds 260ci economy V8 (110 hp/205 lb-ft) in a full-size Delta 88 chassis. The 350 diesel ended up being a little faster—0-60 in 17.5 versus 20.8 for the 260 in the same 4,500-pound ’75 Cutlass test car. Diesel fuel economy was way better— 26.5 mpg versus 19.5 at a steady 55 mph and 21.4 mpg versus 16.7 on the EPA composite test. The 1978 production diesels were EPA rated at 21/30/24 in the full-size platforms. The same car with a 350 V8 gasser delivered 15/22/17. The diesel option cost $740 in a 98 Olds where the base engine was the 350 gas V8.

Meet the Oldsmobile 350 LF9 Diesel

The original 350 diesel “D” block shared the same 4.047×3.385 bore and stroke as the V8 gasser and the same general dimensions, but was only 75 pounds heavier. The complete diesel car was only 135 pounds heavier than the gasser, half of that being the second battery. The internal bulkheads and main bearing support webs of the D block were beefed up and the deck thickness increased. The nodular iron crankshaft was similar to the gas V8’s, but main bearing diameters were enlarged from 2.5 to 3 inches, the cheek structures were increased in size, and the pin lightening holes were eliminated. The connecting rods were significantly enlarged and the piston pin diameter went from 0.978 to 1.11 inches. Needless to say, the pistons were completely different, with steel inserts behind the top compression ring. The compression ratio was a whopping 22.5:1. 

The heads were completely new but the valves were the same size as the gas 350’s. The heads were held down by then-new TTY (Torque To Yield) style bolts with four bolts per cylinder. The cam profile was altered to suit the diesel and the camshaft material was improved from ordinary cast iron to hardened Conkerall iron. The lifters were a tungsten-titanium alloy steel. The cam and injection pump was driven by a double roller chain.

The engine was fueled by a Roosa-Master DB-2 rotary pump from Stanadyne fed by a mechanical lift pump. The injectors also came from Stanadyne and were a new design they called Pencil Nozzles. They had two 0.017-inch orifices (0.014-inch in California) and popped at 1,800 psi.

The Oldsmobile diesel was introduced on September 13, 1977, in the Delta 88 and Ninety-Eight platforms, as well as the Custom Cruiser station wagon and the Chevy C10 pickup. For mid-year 1978, the mid-sized Cadillac Seville, which Cadillac liked to think of as its Mercedes-Beater, also got the diesel option.

All Hell Breaks Loose

The launch started well and the press favorably compared the Oldsmobile diesels to Mercedes. Surveys done of new customers early in ’78 were reported to be 97 percent positive. Olds was selling a lot of diesels, about 60,000 that first year, plus the Chevy trucks and Sevilles (a total of about 129,000 engines). The American public appeared to be accepting the diesel and its quirky ways. Then the fecal matter hit the fan. 

The head gaskets failed. Four TTY head bolts were not always enough to hold the heads down. Sometimes they sheared but most times the gasket failed first. Either way, when the car ended up at the dealer, some mechanics didn’t replace the TTY bolts, or they torqued new ones incorrectly, and if the bolts didn’t break the first time, they did the second. Sometimes the head gasket failure started slowly, contaminating the oil and killing the bearings and/or the camshaft before the head gasket blew.

Injection pump and injector failures occurred. Often this was due to water in the fuel (common in that era). To save money, GM had opted NOT to include a water separator, a water-in-fuel sensor or a tank drain. In some cases, an injection pump failure occurred because people added an alcohol-based “drygas” product.

Camshafts were going flat, despite the improved materials. If it didn’t come from an internal coolant leak it was often related to the lubricants used. GM prescribed a strict 3,000-mile oil change interval to protect against soot buildup, which was made worse by the EGR system, and there wasn’t much fudge factor in the oil change interval. The lubricant specified was a diesel-certified API CE/CD oil, uncommon at gas stations and car repair shops of the day. Non-diesel-rated oil was being used both for changes and top-off, often with some “expert” telling the owner: “It’ll be fine!”

Lower ends were failing. If it didn’t come due to contaminated, incorrect or sooted oil, the “chicken” in that scenario was broken or pulled main bearing cap bolts. Turns out the threads weren’t tapped deeply enough and the bolts were too short. The oil pump driveshaft had a tendency to shear off, but from what little detail is available, it looks like this was often a side effect of oil sludging due to coolant or soot contamination.

Despite it being a stout double roller design, timing chains stretched. This didn’t cause a sudden catastrophic failure but retarded the cam and pump timing, leading to poor performance, higher EGTs, increased noise, excess smoke, hard starting and more strain on the weak head gaskets. This problem was easily fixable by resetting the timing and, if caught early, was no harm in and of itself. 

Finally, it came to light that dealer personnel were in an informational vacuum when it came to dealing with the many warranty problems rolling in. A good number of the follow-up failures were due to inadequate repairs the first time around. The non-dealer repair shops were even deeper in the dark, and more inclined to “wing it.” That was a two-edged sword that sometimes yielded good but non-GM-authorized fixes, and other times hackmeister repairs that added to the car owner’s trouble.

The Blowback on GM

Class action lawsuits ensued and we can thank the Olds 350 for bringing us the Lemon Law, which forces manufacturers to buy back defective cars. The J.D. Power Company sprang into prominence when it published a big survey on the 350 diesel problems. GM spent millions upon millions in paying off claims and has yet to fully get past the reputational hits. Surviving executives and engineers from that time period are probably still experiencing PTSD events.

The Hit on Owners

Based on period sources, an estimated 25 percent of everyone who bought an Olds diesel in the ’78-79 model years had major trouble. They faced a lot of obstacles at first with the inability of GM to fix the cars properly. There are tales of people spending exorbitant amounts of money to get the cars fixed after the warranty ran out. The resale value of Olds diesels went straight into the sewer. Even people who had no trouble with their Olds diesels felt the pain. Fearing a problem, they preemptively attempted to trade them in, and found dealers offering dismal trade-in value or even refusing to take them in trade. 

Shared Blame

GM was the chicken that laid the bad eggs. Barring a better initial product, a faster response to the problems could have saved many headaches. Some of the heat must also go to service people, some of them representatives of General Motors, who dropped the ball and added to the problem. Finally, shame on the owners who couldn’t be bothered to read or follow the recommendations in their owner’s manuals. 

The Legacy

There was a time when the words “Oldsmobile” and “diesel” could not be used together without the speaker hawking a big loogie onto the ground. Forty years later, the legacy of that event is still very evident. There isn’t much doubt the fallout soured the majority of the American public on diesel. It’s also true that the problems were magnified in the retelling and it became fashionable to bash GM.

There were a lot of Olds diesels that had no trouble at all, or the problems that occurred were dealt with satisfactorily. The better dealers and techs stayed up on the problem and once GM realized they had a major PR issue, they encouraged dealers to take proactive steps. Competent techs, responsible dealers and diligent owners avoided most of the trouble. When working well, the cars were nice drivers and the fuel economy was just what gas-crunch-shocked owners needed. If GM had spent a little more time on the details, they could have had their Mercedes-Beater and been credited as the foundation of the American diesel car world, not the destroyer of it. 

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FREQUENTLY ASKED QUESTIONS

What are the specifications of the 1968-1970 Oldsmobile 350 CID W-31 V-8 engine?

Specifications of the 1968-1970 Oldsmobile 350 CID W-31 V-8 Engine

The Oldsmobile 350 CID W-31 V-8 engine was a powerful option available with manual transmissions from 1968 to 1970. Here’s a detailed look at its key features:

• Engine Type:V-8 with overhead valves housed in a robust cast iron block.
• Displacement:350 cubic inches (CID).
• Bore and Stroke:Measures 4.057 inches by 3.385 inches.
• Compression Ratio:A high-performance 10.50:1.
• Power Output:
  • Horsepower:325 at 5400 RPM.
  • Torque:360 lb-ft at 3600 RPM.
• Bearings:Equipped with five main bearings for enhanced durability.

Valve and Cam Specifications

• Valve Head Size:
  • Intake:Ranges from 2.003 to 1.990 inches.
  • Exhaust:Ranges from 1.629 to 1.619 inches.
• Hydraulic Valve Lifters:Ensures smooth operation and reduced maintenance.
• Camshaft Details:
  • Duration:308° for both intake and exhaust.
  • Overlap:82°
  • Lift:474 inches for both intake and exhaust.

Carburetor Information

• Utilizes a Rochester Quadra-jet 4-barrel carburetor, specifically tuned for manual transmissions (model 7028255).

This engine was known for its strong performance characteristics, making it a favorite among enthusiasts during its production run.

 

What were the different variants of the Oldsmobile 350 CID engine available from 1968 to 1970?

Oldsmobile 350 CID Engine Variants (1968-1970)

The Oldsmobile 350 CID engine was available in several variants from 1968 to 1970, each offering unique specifications and performance capabilities. Here’s a breakdown of these engine options:

1968 Variants

1. Base V-8 (All Transmissions)
   • Configuration: Overhead valves, cast iron block
   • Displacement: 330 cubic inches
   • Power: 250 HP at 4400 RPM
   • Torque: 355 lb-ft at 2600 RPM
   • Compression Ratio: 9.0:1
   • Carburetor: Two-barrel Rochester for both manual and automatic transmissions
2. Optional V-8 (All Transmissions)
   • Displacement: 350 cubic inches
   • Power: 310 HP at 4800 RPM
   • Torque: 390 lb-ft at 3200 RPM
   • Compression Ratio: 10.25:1
   • Carburetor: Four-barrel Rochester for both transmission types
3. Optional W-31 V-8 (Manual Transmission Only)
   • Displacement: 350 cubic inches
   • Power: 325 HP at 5400 RPM
   • Torque: 360 lb-ft at 3600 RPM
   • Compression Ratio: 10.50:1
   • Features: Unique camshaft profile and valve head sizes
   • Carburetor: Quadra-jet four-barrel specifically for manual transmission

1969 Variants

The 1969 offerings mirrored those available in 1968, with each engine variant maintaining similar technical specifications and performance parameters.

1. Base V-8 (All Transmissions)
   • Identical to the 1968 model in terms of power and components
2. Optional V-8 (All Transmissions)
   • Matching the 1968 specifications with a 350 CID displacement
3. Optional W-31 V-8 (Manual Transmission Only)
   • Retained the 1968 features, maintaining its place as a high-performance option

1970 Variants

1. Base V-8 (All Transmissions)
   • Consistent with previous years in terms of power output and design
2. Optional V-8 (All Transmissions)
   • Slight adjustment in camshaft lift specifications, but maintaining prior performance metrics
3. Optional W-31 V-8 (Manual Transmission Only)
   • Continued its reputation for performance with a focus on high-rev capabilities and precise valve mechanics

These engine variants offered a range of options for drivers, from reliable performance to more high-octane thrills, depending on the year and model. Each variant was defined by its unique combination of horsepower, torque, and detailed specifications that catered to diverse driving needs.

 

What made the 1968-1970 Oldsmobile 350 CID W-31 V-8 engine a notable performer?

The 1968-1970 Oldsmobile 350 CID W-31 V-8 engine garnered attention for several compelling reasons, establishing itself as a formidable contender among muscle car enthusiasts of its era. Here’s what set it apart:

1. Innovative Engineering: This engine utilized the ingenious pairing of 330 CID heads with the larger valves from the 400 CID model, providing a competitive edge with a simple yet effective upgrade. This clever engineering solution helped maximize power from a smaller displacement.
2. Exceptional Power Output: In almost stock form, it achieved the impressive figure of 1 horsepower per cubic inch, a benchmark of performance excellence. With further modifications, these engines could output well over 400 horsepower, making them formidable on the drag strips.
3. Balanced Performance: The engine struck a remarkable balance between power and drivability. Featuring a lighter design, it was paired with the excellent handling characteristics of the 442 suspension system. This not only enhanced the car’s agility but also made it more cost-effective than some of its larger counterparts, which faced higher insurance premiums for excess horsepower.
4. Technical Specifications:
   • Displacement: 350 CID
   • Bore and Stroke: 4.057″ x 3.385″
   • Compression Ratio: 10.50:1
   • Horsepower: Rated at 325 @ 5400 RPM
   • Torque: 360 lb-ft @ 3600 RPM
   • Valvetrain: Hydraulic valve lifters and a high-performance camshaft similar to the W-30, enhancing its breathing capabilities at higher RPMs.
   • Carburetor: Equipped with the Rochester Quadra-jet 4-barrel, known for its efficient fuel delivery.
5. Performance in Racing: Despite being rated conservatively at lower RPMs, the engine’s true potential unfolded as the RPMs increased. Fully race-prepped versions showed significant gains, achieving quarter-mile times in the 12.5-second range, affirming its prowess on the track.

In essence, the Oldsmobile 350 W-31 engine was a masterclass in achieving high performance with calculated engineering tweaks, offering muscle car fans a powerful and agile option that did not break the bank.

 

How did Oldsmobile’s marketing and engineering strategies position the 350 CID V-8 as a competitive option?

Oldsmobile strategically positioned the 350 CID V-8 as a competitive powerhouse by capitalizing on its strengths and market opportunities. First, they recognized the excitement surrounding Chevrolet’s small block engines, which were favored for their affordability and drivability in mid-sized cars. Leveraging this insight, Oldsmobile saw potential for their soon-to-be-released engine, identifying a niche where it would excel.

A crucial part of their strategy involved engineering foresight. By integrating the lighter 350 CID V-8 into the Cutlass, coupled with the advanced suspension system from the 442, they created a vehicle that promised superior handling. This decision offered consumers an option that stood out not just for performance but also for affordability—an attractive alternative to pricier models.

Oldsmobile’s marketing also capitalized on regulatory landscapes, such as insurance premiums impacting cars with engines over 400 HP. By offering a capable yet more accessible engine configuration, they alleviated the financial burden usually associated with high-performance vehicles.

In summary, Oldsmobile skillfully balanced engineering innovation and market savvy to position the 350 CID V-8 as an appealing choice, emphasizing both performance and cost-effectiveness to allure a broad segment of car enthusiasts.

 

How did Oldsmobile rate the horsepower of the W-31 engine, and what were its actual capabilities?

Oldsmobile rated the horsepower of the W-31 engine at a lower RPM to present a more modest figure. This strategic decision masked the engine’s full power potential. When pushed beyond 5400 RPM, the engine exhibited a significant increase in horsepower, reaching over 400 HP with full race preparation at 6500 RPM. This substantial boost in performance was evident in its quarter-mile times, which were impressively in the 12.5-second range.

 

How did the Oldsmobile W-31 perform in terms of torque and handling?

The Oldsmobile W-31 delivered impressive performance, particularly in terms of torque and handling. It consistently provided robust low-speed torque, making it a joy to drive at slower speeds without any struggle. This power enabled smooth cruising, even when equipped with 3.90:1 rear gears.

When it came to more aggressive driving, the W-31 truly shone. It offered a powerful surge when accelerating, showcasing its capability to handle demanding driving conditions effortlessly. The balance between everyday drivability and raw power made the W-31 a standout performer in its class.

 

What were some of the key tests and reviews conducted on the 1968-1970 Oldsmobile W-31?

Key Tests and Reviews of the 1968-1970 Oldsmobile W-31

The Oldsmobile W-31, a high-performance vehicle from the late 1960s, underwent a series of rigorous tests and reviews that highlighted its capabilities and charm. Here are some notable assessments:

• 1968 Trio Test: This comprehensive evaluation included the W-31 alongside its contemporaries, showcasing its strengths and areas where it outpaced similar models.
• 1968 Road & Drag Test: A detailed analysis that focused on its road performance and drag racing prowess. These tests provided insights into its real-world handling and speed capabilities.
• Three-Part Build and Test Series:
  • Part One: An initial look into the design and engineering behind the W-31.
  • Part Two: Focused on performance tuning and setup.
  • Part Three: Offered a holistic view of the vehicle’s adaptability and robustness under various conditions.
• 1969 Road Tests: Multiple evaluations conducted over this period put the 1969 version of the W-31 through its paces, emphasizing advancements and improvements from previous models.

These tests collectively contributed to understanding the W-31’s place in automotive history, highlighting its appeal among enthusiasts for both its performance and design excellence.

 

How did the Oldsmobile “Ram Rod” 350 CID V-8 evolve from its 330 CID predecessor?

The Evolution of the Oldsmobile “Ram Rod” 350 CID V-8

The evolution of the Oldsmobile “Ram Rod” 350 CID V-8 is rooted in its predecessor, the 330 CID engine, which initially dazzled the hot rod community during the 1964 muscle car era. At first, the 330 CID engine’s potent performance gained attention but eventually became the workhorse for models like the Cutlasses and F-85s, overshadowed when the larger 400 CID V-8 debuted for the 442.

Oldsmobile engineers, however, had high hopes for the 330 CID engine. They knew it had the ability to generate impressive horsepower while remaining reliable under stress. Despite this potential, the 330 seemed destined for obscurity until a series of racing trends altered its trajectory.

Racing Influence and Tactical Innovations

The 1960s racing scene, particularly the emergence of new series under SCCA, demanded innovative engines. These series initially imposed a 5-liter (302 CID) ceiling, later expanding to a 6-liter (366 CID) limit. This context saw the Oldsmobile engineers and racers embrace modifications within stock blocks—a strategy limited only by the rules governing aftermarket parts.

Oldsmobile’s interest in racing meant experimenting with big block heads on the 330, striving to boost performance. Although these attempts enhanced the engine’s top-end potential, early versions suffered from lackluster low-end torque. By 1967, key engineering insight led to adapting the superior valves from the 400 CID engine to the 330’s heads, a change that significantly increased power output.

Rediscovering Potential and Market Strategy

The remarkable results from this modification saw the 330 produce one horsepower per cubic inch in an almost stock format, exceeding 400 horsepower with further tuning. This newfound performance prowess was short-lived in the racing context, as regulations shifted towards larger engines like the 7-liter big block, nudging Oldsmobile to reconsider its strategy.

Within the automotive market, Oldsmobile noticed the popularity of Chevrolet’s small-block engines in mid-sized vehicles, mainly due to affordability and drivability. Recognizing this trend, Oldsmobile prepared to introduce the 350 CID V-8. The new engine seamlessly integrated into competitive racing classes and improved vehicle handling due to its lighter weight when paired with the 442’s suspension setup. Moreover, it promised cost savings and avoided the high insurance rates associated with high-powered vehicles, presenting a balanced performance package.

The Oldsmobile “Ram Rod” 350 CID V-8 thus emerged from the 330 CID not just as an evolution but as a strategic response that involved engineering ingenuity, market dynamics, and the pursuit of accessible performance.

 

What engine specifications were available for the Oldsmobile 330 CID from 1964 to 1967?

Oldsmobile 330 CID Engine Specifications (1964–1967)

The Oldsmobile 330 CID engine was a versatile and powerful small block V-8 that evolved from 1964 to 1967, offering a range of configurations across different years and models. Here’s a concise breakdown of its specifications:

1964 Engine Options

1. Base V-8
   • Horsepower: 230 HP at 4400 RPM
   • Torque: 325 lb-ft at 2400 RPM
   • Compression Ratio: 9.0:1
   • Carburetor: Rochester 2-barrel
2. Optional V-8
   • Horsepower: 290 HP at 4800 RPM
   • Torque: 355 lb-ft at 2800 RPM
   • Compression Ratio: 9.0:1
   • Carburetor: Rochester 4-barrel
3. 442 V-8 (Manual Only)
   • Horsepower: 310 HP at 5200 RPM
   • Torque: 355 lb-ft at 3600 RPM
   • Compression Ratio: 10.25:1
   • Carburetor: Rochester 4-barrel

1965 Engine Options

1. Base V-8
   • Horsepower: 250 HP at 4800 RPM
   • Torque: 335 lb-ft at 2800 RPM
   • Compression Ratio: 9.0:1
   • Carburetor: Rochester 2-barrel
2. Optional V-8
   • Horsepower: 315 HP at 5200 RPM
   • Torque: 360 lb-ft at 3600 RPM
   • Compression Ratio: 10.25:1
   • Carburetor: Rochester 4-barrel

1966 Engine Options

1. Base V-8
   • Horsepower: 250 HP at 4800 RPM
   • Torque: 335 lb-ft at 2800 RPM
   • Compression Ratio: 9.0:1
   • Carburetor: Rochester 2-barrel
2. Optional Low Compression V-8
   • Horsepower: 310 HP at 5200 RPM
   • Torque: 340 lb-ft at 3600 RPM
   • Compression Ratio: 9.0:1
   • Carburetor: Rochester 4-barrel
3. Optional High Compression V-8
   • Horsepower: 320 HP at 5200 RPM
   • Torque: 360 lb-ft at 3600 RPM
   • Compression Ratio: 10.25:1
   • Carburetor: Rochester 4-barrel

1967 Engine Options

1. Base V-8
   • Horsepower: 250 HP at 4800 RPM
   • Torque: 335 lb-ft at 2800 RPM
   • Compression Ratio: 9.0:1
   • Carburetor: Rochester 2-barrel
2. Optional Low Compression V-8
   • Horsepower: 310 HP at 5200 RPM
   • Torque: 340 lb-ft at 3600 RPM
   • Compression Ratio: 9.0:1
   • Carburetor: Rochester 4-barrel
3. Optional High Compression V-8
   • Horsepower: 320 HP at 5200 RPM
   • Torque: 360 lb-ft at 3600 RPM
   • Compression Ratio: 10.25:1
   • Carburetor: Rochester 4-barrel

Each version of the Oldsmobile 330 CID between 1964 and 1967 came with distinctive performance characteristics, allowing enthusiasts to select the engine that best matched their needs for power and driving style.

 

How did modifications to Oldsmobile engines impact their performance in racing?

In 1967, a pivotal change occurred in the realm of Oldsmobile engines that significantly impacted their performance in racing. Dale Smith, the head of engineering and the 442 program, introduced an innovative idea that transformed engine capabilities. By equipping the 330 cubic inch displacement (CID) engine with valves originally designed for the 400 CID engine, a remarkable performance boost was achieved.

This modification, surprisingly simple yet effective, allowed the 330 CID motor to produce nearly one horsepower per cubic inch in its almost standard configuration. When further enhanced, it delivered outputs exceeding 400 horsepower. Such improvements propelled the engines into a competitive position in racing circuits.

However, a shift in racing regulations, namely the SCCA Series’ move to Group 7 (with engines up to 7 liters), changed the landscape, redirecting attention toward larger engines like the big block Chevrolet. Nonetheless, the modifications underscored the potential of innovative engineering solutions in elevating engine performance on the racing track.

 

How did the racing scene in the 1960s influence the development of Oldsmobile engines?

How the 1960s Racing Scene Influenced Oldsmobile Engine Development

The 1960s was a pivotal era for motorsports, sparking a worldwide enthusiasm for race cars. This boom led to the creation of numerous racing series, notably within the Sports Car Club of America (SCCA), which became a hotbed for innovation. These series embraced American V-8 engines, often integrated into a variety of race car chassis, from sleek European models to those built in local garages.

Engine Specifications and Modifications

Initially, these competitions imposed strict regulations like cubic inch limitations—starting with 5 liters (302 CID) and later expanding to 6 liters (366 CID). While stock engine blocks were mandatory, teams enjoyed almost limitless freedom with modifications. The only exception was the prohibition of advanced aftermarket cylinder heads, encouraging creative engineering.

The Oldsmobile Strategy

Amidst this vibrant racing culture, Oldsmobile’s marketing and engineering divisions observed a trend: Chevrolet’s small block engines were gaining popularity due to their affordability and ease of use in mid-sized cars. This insight prompted Oldsmobile to develop its own competitive engine—the soon-to-be-released 350 CID V-8.

Recognizing a Winning Opportunity

Oldsmobile foresaw that their new 350 engine would fit perfectly into the NHRA’s E/S class, a potential advantage in racing performance. The strategic deployment of this lighter engine in a Cutlass model, paired with suspension components from their high-performance 442 line, promised exceptional handling. Additionally, this setup offered a cost-effective alternative without incurring the substantial insurance rates for models exceeding 400 horsepower.

In essence, the racing enthusiasm of the 1960s pushed Oldsmobile to innovate, creating powertrains that were not only competitive on the track but also appealing and accessible to everyday car enthusiasts.

 

What changes were suggested by Dale Smith to improve the performance of Oldsmobile engines in 1967?

In 1967, Dale Smith, who was responsible for engineering and overseeing the development of the 442 program, proposed a performance-enhancing modification for Oldsmobile engines. He recommended equipping the 330 cubic inch displacement (CID) cylinder heads with the larger valves from the 400 CID engine. This suggestion was a straightforward solution that increased the efficiency and power of the engine without requiring complex modifications.

 

What role did the 330 CID engine play in the success of the 1964 Oldsmobile 442?

The Role of the 330 CID Engine in the 1964 Oldsmobile 442’s Success

The 1964 Oldsmobile 442 made a significant mark in the muscle car era, largely due to the capabilities of its 330 CID V-8 engine. This engine initially demonstrated its potential by being robust and reliable, even when it wasn’t the most powerful on the market. Despite this, it offered a solid performance foundation, essential for building speed and power.

As the car evolved, Oldsmobile engineers sought ways to maximize the 442’s performance. In 1964, the main challenge was the limited availability of speed parts for the 330 engine. However, by 1965 and early 1966, the installation of big block heads transformed the engine’s capability. These big block heads worked because Oldsmobile’s small and big block engines were interchangeable in terms of some parts, like deck height and crankshaft dimensions. Even with this upgrade, achieving high torque at low speeds remained challenging.

The major breakthrough came in 1967. Dale Smith, leading the engineering efforts at Oldsmobile, proposed a clever modification: equipping the 330 CID heads with the larger valves from the 400 CID. This simple tweak dramatically enhanced the engine’s airflow, boosting its horsepower output impressively.

Ultimately, this innovation enabled the 330 CID engine to deliver 1 horsepower per cubic inch in near-stock form. When further modified, it could exceed 400 horsepower, affirming its critical role in the 442’s performance success. The adaptability and potential of the 330 CID were instrumental in securing the 442’s reputation as a formidable muscle car competitor.

 

What notable achievements did the McLaren M1A Oldsmobile accomplish with its Oldsmobile engine?

Notable Achievements of the McLaren M1A with its Oldsmobile Engine

The McLaren M1A, outfitted with an Oldsmobile engine, made significant strides in the world of racing. It was originally sold to Ralph Salyer, a well-known American privateer racer.

One of its remarkable achievements was in 1965 during the SCCA National Championship run-offs held at Daytona. Behind the wheel of this machine, Salyer clinched the pole position, establishing himself as one of the fastest drivers of that year. This extraordinary performance highlighted the car’s exceptional speed and competitiveness on the track.

The car was affectionately known as the ‘Cro-Sal’ special, a nod to the collaboration between Salyer and his dedicated mechanic, Gene Crowe. This partnership helped push the McLaren to its peak performance during its time with the Oldsmobile engine.

 

What records and achievements did the W-31 engine accomplish in NHRA events and at Bonneville?

W-31 Engine’s Noteworthy Achievements

Dominance in NHRA Events

The W-31 engine stood out in the National Hot Rod Association (NHRA) competitions during its three-year production span. It dominated its class, particularly in the stock Eliminator category at the 1968 Springnationals. The vehicle set impressive times and speeds, clinching several records. For instance, it achieved a remarkable elapsed time of 12.70 seconds and reached a speed of 107.65 mph in its class. These records showcased the engine’s formidable performance and engineering excellence.

Record-Breaking Performance at Bonneville

Beyond NHRA events, the W-31 didn’t just rest on its laurels. It was also taken to the legendary Bonneville Salt Flats, a venue known for speed trials and pushing automotive boundaries. There, the W-31 set class record speeds that endured for many years, further cementing its legacy as a powerhouse in automotive history.

In summary, the W-31 engine’s impact was significant both on the drag strip and in setting long-standing speed records at prestigious arenas like Bonneville. Its legacy is one of speed, power, and championship-caliber performance.

 

What are the changes in engine specifications between the 1969 and 1970 model years for Oldsmobile V-8 engines?

Comparing 1969 and 1970 Oldsmobile V-8 Engine Specifications

Enthusiasts tracking the evolution of Oldsmobile’s V-8 powerplants from 1969 to 1970 will appreciate the subtle refinements that marked each model year. While the engine options remained consistent, several specification tweaks underscored Oldsmobile’s attention to performance details.

Base V-8 (All Transmissions)

Across both years, the base V-8 retained its displacement, bore and stroke, and general layout. Output was steady at 250 horsepower and 355 lb-ft of torque, paired with a 9.0:1 compression ratio. Both model years utilized overhead valves and a cast iron block, with the familiar five main bearings and hydraulic valve lifters. Camshaft specifications, including duration and overlap, remained consistent, and both engines were topped with a Rochester 2-barrel carburetor, though carburetor part numbers differed year to year.

Optional V-8 (All Transmissions)

The optional 350 CID V-8 maintained its robust 310 horsepower and 390 lb-ft of torque. Core engine architecture was unchanged, and compression stayed at 10.25:1. Notably, camshaft lift saw a slight decrease in 1970 (from 0.435″ to 0.400″ on both intake and exhaust), a change reflecting minor engineering updates aimed at balancing efficiency and performance. The engine continued with a Rochester 4-barrel carburetor, but, as with the base engine, updated part numbers identified each year’s unit.

W-31 V-8 (Manual Transmission Only)

The high-performance W-31 V-8 preserved its standout characteristics year-over-year: 325 horsepower at 5400 RPM, 360 lb-ft at 3600 RPM, and a high 10.50:1 compression ratio. Larger valve head sizes and aggressive camshaft specs lent the W-31 its racing prowess, with identical bore, stroke, and Quadra-jet 4-barrel carburetion. Camshaft timing and lift figures were unchanged between the years, ensuring the W-31’s reputation for race-ready power remained intact.

Summary of Refinements

• Carburetor part numberswere revised for both base and optional engines.
• Camshaft liftfor the optional 350 V-8 decreased in 1970.
• Performance figures and core architecturewere consistent, signaling a period of refinement rather than reinvention.

Steady progress and minor updates characterized Oldsmobile’s engineering approach at the turn of the decade, ensuring each V-8 variant delivered a trusted blend of power and dependability—qualities that have kept these engines at the heart of classic car culture.

 

What types of carburetors are used in manual and automatic transmission versions of these engines?

Carburetor Variations by Transmission Type

When it comes to feeding fuel into the 350 CID Oldsmobile V-8 engines from 1968 to 1970, carburetor configuration depends on both the engine option and the type of transmission chosen.

• Base and Mid-Performance Engines:
  • Models equipped with a manual transmission typically receive a two-barrel or four-barrel carburetor, depending on horsepower rating.
  • Automatic versions are matched with their own dedicated carburetor models to optimize shifting and drivability.
• Optional and W-31 High-Performance Engines:
  • For the W-31 and high-output variants, manual transmission models are fitted with a performance-tuned four-barrel carburetor—specifically the Rochester Quadra-jet—designed to maximize airflow and fuel mixture at higher RPMS.
  • Automatic transmission models are paired with their own four-barrel version of the Quadra-jet, ensuring smooth power delivery suited to the automatic’s characteristics.

In summary, while both manual and automatic transmissions receive four-barrel carburetors for the upper-tier engines, each is precisely calibrated to match the particular needs of its respective transmission type. This attention to detail ensured optimal performance, no matter which pedal you preferred to press.

 

Which carburetors were used on the 1968 350 CID V-8 engines, and how do they vary by transmission and air conditioning?

Carburetor Options by Transmission and Air Conditioning

For the 1968 350 CID V-8 engines, carburetor selection depended on both the transmission type and whether the vehicle was equipped with air conditioning.

• Manual Transmission:Fitted with a Rochester 2-barrel carburetor (part number 7028156).
• Automatic Transmission:Equipped with a distinct Rochester 2-barrel unit (part number 7028157).
• Models with Air Conditioning:Used another specific version (part number 7028154) to accommodate the added load and maintain performance balance.

Each setup ensured optimal fuel delivery tailored to the drivetrain and accessory configuration, underscoring Oldsmobile’s attention to maximizing both reliability and drivability across all variants.

 

What are the specific differences between the base, optional, and W-31 performance versions of the Oldsmobile 350 CID engine?

Base V-8 (All Transmissions)

• Familiar Foundations:Core specifications remain consistent with previous years.
  • Overhead valves, cast iron block construction
  • Displacement: 330 CID
  • Bore and stroke: 4.057″ x 3.385″
  • Compression ratio: 9.0:1
  • Horsepower: 250 @ 4400 RPM
  • Torque: 355 @ 2600 RPM
  • Five main bearings with hydraulic valve lifters
  • Camshaft: Intake duration 250°, exhaust duration 264°, overlap 36°, lift 0.435″ (intake & exhaust)
  • Rochester 2-barrel carburetor: #7029155 (manual), #7028156 (automatic)

Optional V-8 (All Transmissions)

• Advancements in Engineering:Continues delivery of high-performance metrics with slight modifications in valve lift for enhanced efficiency.
  • Overhead valves, cast iron block
  • Displacement: 350 CID
  • Bore and stroke: 4.057″ x 3.385″
  • Compression ratio: 10.25:1
  • Horsepower: 310 @ 4800 RPM
  • Torque: 390 @ 3200 RPM
  • Five main bearings, hydraulic valve lifters
  • Camshaft: Intake duration 250°, exhaust duration 264°, overlap 36°, lift 0.435″ (intake & exhaust)
  • Rochester 4-barrel carburetor: #7028250 (manual), #7028254 (automatic)

W-31 V-8 (Manual Transmission Only)

• Champion Performance:Maintains its high-performance status with horsepower and torque continuity, offering enthusiastic driving dynamics.
  • Overhead valves, cast iron block
  • Displacement: 350 CID
  • Bore and stroke: 4.057″ x 3.385″
  • Compression ratio: 10.50:1
  • Horsepower: 325 @ 5400 RPM
  • Torque: 360 @ 3600 RPM
  • Five main bearings
  • Valve head size: Intake 2.003″–1.990″, Exhaust 1.629″–1.619″
  • Hydraulic valve lifters
  • Camshaft: Intake duration 308°, exhaust duration 308°, overlap 82°, lift 0.474″ (intake & exhaust)
  • Rochester Quadra-jet 4-barrel carburetor (#7028255, manual only)

 

What are the distinguishing engineering features between the engine versions?

Each engine features overhead valves and a cast iron block. The W-31 differentiates itself with larger valve heads and a performance camshaft, while the standard and optional V-8s focus on balanced performance and reliability. Carburetor setups and compression ratios further distinguish the three, with the W-31 built for maximum output.

 

Which engines are available with which transmissions?

The base and optional V-8s are available with both manual and automatic transmissions. The W-31 engine, however, is offered exclusively with a manual transmission.

 

What is the displacement of each engine?

The base V-8 displaces 330 cubic inches, while both the optional V-8 and the W-31 are 350 cubic inches.

 

Are there differences in main bearings or valve lifters?

All three engines utilize five main bearings and hydraulic valve lifters.

 

What are the valve head sizes for the W-31 version?

Intake valve heads on the W-31 measure just over 2 inches, while the exhaust valves come in at approximately 1.62 inches.

 

What is the camshaft specification (duration, overlap, lift) for each engine?

The base and optional V-8s share cam profiles with intake duration at 250°, exhaust at 264°, a 36° overlap, and .435-inch lift on both intake and exhaust. The W-31 cam is more aggressive, showing 308° duration, 82° overlap, and .474-inch lift for both intake and exhaust.

 

What type and model of carburetor does each engine use?

The base engine is equipped with a 2-barrel Rochester carburetor, with model numbers tailored for manual and automatic transmissions. The optional V-8 uses a 4-barrel Rochester, again with specific models for each transmission type. The W-31 gets a Rochester Quadra-jet 4-barrel, designated for manual transmissions only.

 

What are the bore and stroke dimensions for each engine?

All three engines—base, optional, and W-31—feature a bore of 4.057 inches and a stroke of 3.385 inches.

 

What is the compression ratio for each engine?

The base V-8 operates with a 9.0:1 compression ratio. The optional V-8 raises this to 10.25:1, while the W-31 engine is tuned even higher at 10.50:1.

 

What are the exact horsepower and torque ratings for each engine version?

The base V-8 produces 250 horsepower at 4,400 RPM and 355 lb-ft of torque at 2,600 RPM. The optional V-8 increases those numbers to 310 horsepower at 4,800 RPM and 390 lb-ft at 3,200 RPM. The high-performance W-31 variant delivers 325 horsepower at 5,400 RPM and 360 lb-ft at 3,600 RPM.

 

What are the differences in camshaft specifications between the standard and W-31 high-performance engine options?

Crucial to its success were components like big block valves and the camshaft from the formidable 1966-67 big block W-30, enhancing performance and reliability. The camshaft itself was no ordinary piece: it featured intake duration at 250°, exhaust at 264°, with a 36° overlap and a lift of 0.435″ for both intake and exhaust. For those seeking even more aggressive specs, later iterations boasted a camshaft with a 308° duration on both intake and exhaust, an overlap of 82°, and lift raised to 0.474″. These robust specs contributed to the engine’s unmistakable character and relentless pull, making it a true standout among its contemporaries.

 

How do the camshaft specifications enable direct comparison between standard and high-performance engines?

By providing side-by-side figures for duration, overlap, and lift, it’s clear the high-performance camshaft is far more aggressive, resulting in greater engine breathing capacity and higher potential output compared to the standard configuration.

 

How do the camshaft specifications quantitatively differ between the standard and high-performance engines?

The high-performance camshaft raises intake and exhaust duration from 250/264 degrees to 308 degrees each, enhances overlap from 36 to 82 degrees, and boosts lift from 0.435 to 0.474 inches.

 

What are the valve lift measurements for the intake and exhaust for each camshaft?

Valve lift on the standard setup is 0.435 inches for both intake and exhaust. On the high-performance camshaft, lift jumps to 0.474 inches for both.

 

What are the valve overlap values for each camshaft?

The standard camshaft features a valve overlap of 36 degrees, while the high-performance camshaft increases overlap significantly to 82 degrees.

 

What are the exact camshaft duration specifications for the intake and exhaust on both the standard and high-performance engines?

The standard camshaft offers an intake duration of 250 degrees and an exhaust duration of 264 degrees. The high-performance variant increases both intake and exhaust durations to 308 degrees each.

 

What role did the Oldsmobile 350 CID W-31 V-8 play in vehicles like the Cutlass and F-85?

Designed for versatility, the 350 CID engine found its place in models such as the Cutlass, leveraging the robust 442 suspension to enhance handling capabilities. This strategic integration made it a hit in terms of performance and cost-effectiveness, even bypassing insurance penalties due to its sub-400 horsepower rating—though, in reality, the engine’s capability far exceeded this figure, especially at higher RPMs.

While many might chalk up the origins of the 350 CID “Ram Rod” V-8 to the earlier success of the 330 CID version in the 1964 442, the story doesn’t stop at mere lineage. The 350 quickly caught the attention of hot rod enthusiasts for its spirited performance in Oldsmobile’s mid-size muscle lineup. Yet, its destiny wasn’t to dominate the drag strip alone; before long, it was making everyday models like the Cutlass and F-85 notably more lively, bringing a dose of excitement to daily driving without the baggage of high insurance costs.

 

How did the role of the 350 CID V-8 change over time?

Over time, the engine transitioned from being a standout in muscle car applications to serving as a spirited upgrade for more mainstream models like the Cutlass and F-85.

 

What was the initial impact or reputation of the engine in performance circles?

When introduced, the 350 CID V-8 quickly captured the attention of performance enthusiasts, thanks to its strong showing in Oldsmobile’s mid-size muscle cars.

 

How did the 350 CID “Ram Rod” V-8 originate, and what is its lineage?

The 350 CID “Ram Rod” V-8 is often thought to have its roots in the success of the earlier 330 CID engine, which powered the 1964 Oldsmobile 442 and earned a strong reputation for performance.

 

How much horsepower and at what RPM do the base and optional Oldsmobile V-8 engines produce?

1967 Variants and Specifications

• Base V-8:
  • Horsepower: 250 HP
  • Torque: 335 lb-ft
  • Compression Ratio: 9.0:1
  • Carburetor: Rochester 2-barrel
  • Displacement: 330 CID
  • Bore and Stroke: 4.057″ x 3.385″
  • Five main bearings
  • Hydraulic valve lifters
  • Camshaft Duration: Intake 250°, Exhaust 264°, Overlap 36°
  • Valve Lift: 0.435″ (intake), 0.435″ (exhaust)
• Optional Low Compression V-8:
  • Horsepower: 310 HP
  • Torque: 340 lb-ft
  • Compression Ratio: 9.0:1
  • Carburetor: Rochester 4-barrel
  • Displacement: 350 CID
  • Bore and Stroke: 4.057″ x 3.385″
  • Five main bearings
  • Hydraulic valve lifters
  • Camshaft Duration: Intake 250°, Exhaust 264°, Overlap 36°
  • Valve Lift: 0.435″ (intake), 0.435″ (exhaust)
• Optional High Compression V-8:
  • Horsepower: 320 HP
  • Torque: 360 lb-ft
  • Compression Ratio: 10.25:1
  • Carburetor: Rochester 4-barrel
  • Displacement: 350 CID
  • Bore and Stroke: 4.057″ x 3.385″
  • Five main bearings
  • Hydraulic valve lifters
  • Camshaft Duration: Intake 250°, Exhaust 264°, Overlap 36°
  • Valve Lift: 0.435″ (intake), 0.435″ (exhaust)

All variants feature overhead valves and a cast iron block, delivering a reliable blend of performance and durability. Whether you’re after the smooth cruising of the base V-8 or the punchier response of the high compression option, these engines laid a solid foundation for the late-‘60s muscle era—no matter which side of the carburetor debate you find yourself on.

 

What are the detailed specs for each engine variant by model year and transmission?

Each model year features base, optional, and high-performance V-8s, with specifications such as horsepower, torque, compression, camshaft, and carburetor model tailored to the engine and transmission pairing. Manual and automatic transmissions sometimes require unique carburetor models; the W-31 is available only with manual transmission and receives upgraded cam and valvetrain components, as well as higher compression and more aggressive tuning.

 

How do compression ratios vary between different years, models, and transmission types?

Compression ratios range from 9.0:1 for base and low-compression engines, up to 10.25:1 for many performance options, and 10.5:1 for high output variants like the W-31. The ratio is highest in the W-31, regardless of year.

 

Which specific carburetor model is used with each engine and transmission combination?

Carburetor specification varies by engine and transmission. Base engines typically use a Rochester 2-barrel, with model numbers differing for manual and automatic transmissions. The 310 HP and W-31 variants use Rochester 4-barrel or Quadra-jet carburetors, each with unique model numbers depending on year and transmission pairing.

 

What are the camshaft specs (duration, lift, overlap) and other internal details for each engine?

Standard engines use a camshaft with intake duration of 250 degrees, exhaust duration of 264 degrees, 36 degrees of overlap, and .435-inch lift for both intake and exhaust. The W-31 performance version upgrades to 308 degrees duration for both intake and exhaust, 82 degrees overlap, and .474-inch lift. All engines feature five main bearings and hydraulic valve lifters; the W-31 also uses larger valves.

 

What is the displacement (CID) of each engine variant, and what are their bore and stroke measurements?

The engines range from 330 to 350 cubic inches of displacement. The common bore and stroke for 350 CID engines is 4.057 inches by 3.385 inches. The base engine in some years is 330 CID, sharing the same bore and stroke.

 

At what RPM does each engine produce its peak torque?

The base 250 HP engine delivers peak torque at 2600 RPM. The 310 HP engine’s maximum torque is found at 3200 RPM, and the W-31’s peak torque is delivered at 3600 RPM.

 

At what RPM does each engine produce its peak horsepower?

The 250 HP variant reaches its maximum horsepower at 4400 RPM. The 310 HP version achieves peak output at 4800 RPM, while the high-performance W-31 (325 HP) does so at 5400 RPM.

 

How did the W-31 engine compare to other engines of its time, such as Chevrolet’s small block V-8?

Recognizing a gap in the market for a high-performance yet affordable engine, Oldsmobile saw an opportunity when they developed their 350 CID V-8 engine. It was designed to compete with the popular Chevrolet small blocks, known for their cost-effectiveness and drivability in mid-sized cars. Oldsmobile predicted their new engine would not only fit the regulatory demands but excel in the NHRA racing scene.

The specs spoke for themselves. The 350 CID V-8 featured a cast iron block, with a bore and stroke of 4.057″ x 3.385″ and five main bearings. It boasted a 10.50:1 compression ratio, putting out 325 horsepower at 5400 RPM and 360 lb-ft of torque at 3600 RPM. Under the hood, big block valves (2.003″-1.990″ intake, 1.629″-1.619″ exhaust) and hydraulic lifters worked in concert with a camshaft borrowed from the 1966-67 W-30 big block: 308° duration on both intake and exhaust, 82° overlap, and 0.474″ lift. Fuel delivery came courtesy of the Rochester Quadra-jet 4-barrel carburetor, with part numbers varying across manual and automatic transmissions between 1968 and 1970.

This engine was integrated into models like the Cutlass, where it partnered with the 442 suspension system to deliver superior handling. Its lighter build provided an edge over heavier competitors, and it was particularly dominant in the NHRA classes during its production. For instance, the Cutlass “Ram Rod” consistently performed well, setting records with its 350/325 HP specs.

Insurance companies were already penalizing cars with over 400 HP, making the 350 V-8 an attractive alternative for performance enthusiasts. Yet, Oldsmobile was clever in its ratings: while officially listed at 325 HP, the engine’s real potential emerged above 5400 RPM, with fully race-prepped versions pushing well beyond 400 HP at over 6500 RPM. This translated into quarter-mile times in the 12.5-second range—numbers that backed up the reputation. The Cutlass “Ram Rod” 350/325 HP set NHRA E/S records in 1968, posting a 12.70-second pass at 107.65 mph, and even clinched victories in Stock Eliminator at the Springnationals. Beyond the drag strip, a W-31 variant made its mark at Bonneville, capturing class record speeds that stood for years.

For Oldsmobile, the stage was set—their 350 CID V-8 wasn’t just a response to the competition; it was a statement of what an affordable, high-performing engine could achieve both on the road and at the track.

 

Who were the notable drivers or events involving the W-31?

The W-31 made its mark in NHRA Stock Eliminator competition, with racers like Ron Garey achieving victories over rivals such as John Dianna. The engine’s prowess was highlighted during prestigious events like the 1968 Springnationals.

 

What was the broader context of the W-31’s introduction in relation to Chevrolet’s small block?

Oldsmobile introduced the W-31 in part to compete directly with Chevrolet’s small block, which was popular in mid-sized cars due to its affordability and ease of use. The W-31 aimed to match or exceed these attributes while offering superior performance.

 

What market and regulatory factors influenced the W-31’s development and marketing?

Oldsmobile needed to navigate insurance surcharges that penalized cars with engines rated over 400 horsepower. By carefully rating the W-31 just below this threshold, they made it more appealing to buyers concerned with insurance costs while still providing strong performance.

 

What specific components or features differentiated the W-31 from competitors?

The W-31 set itself apart with its use of big block-sized valves, a high-performance camshaft from the W-30, and hydraulic lifters. It also featured annually updated Rochester Quadra-jet carburetors tailored for different transmission types, optimizing both street and track performance.

 

How did the W-31 perform in real-world racing and record-setting?

The W-31 proved dominant in NHRA competition, achieving quarter-mile times in the low 12-second range and setting class records, such as a 12.70-second pass at over 107 mph in the E/S class. It also captured class speed records at Bonneville that stood for years, further cementing its legacy in competitive circles.

 

Was the W-31’s horsepower rating accurate or understated?

The published horsepower figure was conservative. Oldsmobile rated the engine at 5,400 RPM, but its true performance potential emerged at higher RPMs—when race-prepped, the W-31 could exceed 400 horsepower above 6,500 RPM. This understated rating was strategic, helping the car fit within certain racing classes and insurance thresholds.

 

How did Oldsmobile achieve higher performance with the W-31?

Oldsmobile enhanced the W-31’s output by incorporating oversized valves typically found in big block engines, and by using the aggressive camshaft design from their earlier W-30 models. These choices allowed the engine to breathe more freely and operate efficiently at higher revolutions, giving it a performance advantage over standard small blocks.

 

What are the detailed technical specifications of the W-31 engine?

The W-31 engine featured a cast iron block with a displacement of 350 cubic inches, a bore and stroke measuring just over 4 by 3.3 inches, and five main bearings. It operated with a compression ratio of 10.5:1, producing 325 horsepower at 5,400 RPM and 360 lb-ft of torque at 3,600 RPM. The engine was equipped with large intake and exhaust valves, hydraulic lifters, and a camshaft with notable duration and lift. Depending on the production year, it used specific versions of the Rochester Quadra-jet four-barrel carburetor.

 

Which engine and carburetor configurations are available with manual and/or automatic transmissions?

1968 Oldsmobile 350 CID Engines

Base V-8 (All Transmissions)

• Displacement and Construction:330 CID, cast iron block with overhead valves.
• Bore and Stroke:057″ x 3.385″.
• Compression Ratio:Set at 9.0:1.
• Power Output:250 horsepower at 4400 RPM, 355 torque at 2600 RPM.
• Key Features:Five main bearings and hydraulic valve lifters.
• Camshaft Specs:Duration—Intake 250°, Exhaust 264°, Overlap 36°, Lift 0.435″ (intake/exhaust).
• Carburetor:Equipped with a Rochester 2-barrel (manual transmission: 7029155; automatic: 7028156).

Optional V-8 (All Transmissions)

• Displacement:350 CID.
• Bore and Stroke:057″ x 3.385″.
• Compression Ratio:25:1.
• Performance Specs:310 horsepower at 4800 RPM and 390 torque at 3200 RPM.
• Key Features:Five main bearings, hydraulic valve lifters.
• Camshaft Specs:Duration—Intake 250°, Exhaust 264°, Overlap 36°, Lift 0.435″ (intake/exhaust).
• Carburetor:Uses a Rochester 4-barrel (manual transmission: 7028250; automatic: 7028254).

W-31 V-8 (Manual Transmission Only)

• Performance:325 horsepower at 5400 RPM, torque of 360 at 3600 RPM.
• Displacement:350 CID, cast iron block with overhead valves.
• Bore and Stroke:057″ x 3.385″.
• Compression Ratio and Valve Details:High compression at 10.50:1, hydraulic lifters.
• Valve Head Size:Intake 2.003″–1.990″; exhaust 1.629″–1.619″.
• Camshaft Specs:Duration—Intake 308°, Exhaust 308°, Overlap 82°, Lift (intake/exhaust) 0.474″.
• Carburetor:Rochester Quadra-jet 4-barrel (manual transmission only, 7029255).

1969 Oldsmobile 350 CID Engines

Base V-8 (All Transmissions)

• Specs Remain Constant:Same displacement, power, and carburetion as the 1968 model.

Optional V-8 (All Transmissions)

• Refinement and Specs:Continues the capability of 310 horsepower and 390 torque with a robust compression ratio.

W-31 V-8 (Manual Transmission Exclusively)

• Slight Upgrades:Maintained power and torque with incremental carburetor system updates.

 

What is the displacement (CID) of each engine option available in 1969 and 1970 Oldsmobile models?

1970 Oldsmobile 350 CID Engines

Base V-8 (All Transmissions)

• Familiar Foundations:Core specifications remain consistent with previous years.
  • Overhead valves, cast iron block, and a displacement of 350 CID.
  • Bore and stroke: 4.057″ x 3.385″.
  • Compression ratio stands at 9.0:1.
  • Power output: 250 horsepower @ 4400 RPM, with 355 lb-ft of torque @ 2600 RPM.
  • Five main bearings and hydraulic valve lifters ensure smooth operation.
  • Camshaft duration: Intake 250°, Exhaust 264°, Overlap 36°, with lift at 0.435″ (intake and exhaust).
  • Rochester 2-barrel carburetor (manual: 7040155, automatic: 7040156).

Optional V-8 (All Transmissions)

• Advancements in Engineering:Continues delivery of high-performance metrics with slight modifications in valve lift for enhanced efficiency.
  • Overhead valves and a robust cast iron block.
  • Displacement: 350 CID, bore and stroke: 4.057″ x 3.385″.
  • Compression ratio: 10.25:1, raising the stakes for spirited driving.
  • 310 horsepower @ 4800 RPM, torque at a hefty 390 lb-ft @ 3200 RPM.
  • Five main bearings and hydraulic valve lifters.
  • Camshaft duration mirrors the base at Intake 250°, Exhaust 264°, Overlap 36°, but with a slightly reduced lift: 0.400″ (intake and exhaust).
  • Rochester 4-barrel carburetor (manual: 7040255, automatic: 7040256).

W-31 V-8 (Manual Transmission Only)

• Champion Performance:Maintains its high-performance status with horsepower and torque continuity, offering enthusiastic driving dynamics.
  • Overhead valves, cast iron block, and 350 CID displacement.
  • Bore and stroke: 4.057″ x 3.385″.
  • Compression ratio dialed up to 10.50:1.
  • Delivers an impressive 325 horsepower @ 5400 RPM and 360 lb-ft of torque @ 3600 RPM.
  • Five main bearings.
  • Intake valve head size: 2.003″–1.990″; exhaust: 1.629″–1.619″.
  • Hydraulic valve lifters, with aggressive camshaft duration (Intake 308°, Exhaust 308°, Overlap 82°) and lift at 0.474″ (intake and exhaust).
  • Rochester Quadra-jet 4-barrel carburetor (70240255 for both manual and automatic).

With these detailed specifications, the 1970 Oldsmobile 350 CID lineup delivers a balanced mix of tradition and tuned athleticism—whether you’re after reliability, a touch of extra punch, or full-throttle performance.

 

What are the valve head sizes (for W-31)?

The W-31’s intake valves range from 1.990 to 2.003 inches, and the exhaust valves measure between 1.619 and 1.629 inches.

 

What is the carburetor model for each engine and transmission pairing?

The base engine uses a Rochester 2-barrel carburetor (manual: 7040155, automatic: 7040156). The optional V-8 employs a Rochester 4-barrel (manual: 7040255, automatic: 7040256). The W-31 comes with a Rochester Quadra-jet 4-barrel (model 70240255).

 

What are the camshaft specifications (duration, overlap, lift)?

The base and optional V-8s share cam specs: intake duration at 250°, exhaust at 264°, overlap at 36°, and lift at 0.400 inches for both intake and exhaust. The W-31 features a more aggressive profile: 308° duration for both intake and exhaust, 82° overlap, and 0.474-inch lift.

 

What type of valve lifters are used?

Hydraulic valve lifters are utilized across all three engine configurations.

 

How many main bearings does each engine have?

All engines are equipped with five main bearings.

 

What is the torque and at what RPM is it achieved?

For the base engine, torque is 355 lb-ft at 2600 RPM. The optional V-8 provides 390 lb-ft at 3200 RPM, while the W-31 generates 360 lb-ft at 3600 RPM.

 

What is the horsepower and at what RPM is it achieved?

The base V-8 produces 250 horsepower at 4400 RPM, the optional V-8 delivers 310 horsepower at 4800 RPM, and the W-31 tops out at 325 horsepower at 5400 RPM.

 

What is the compression ratio for each engine?

The base V-8 has a 9.0:1 compression ratio, the optional V-8 is at 10.25:1, and the W-31 is slightly higher at 10.50:1.

 

What are the bore and stroke measurements for each engine?

All three engines share a bore of 4.057 inches and a stroke of 3.385 inches.

 

What is the displacement (CID) for each engine option?

The base engine is listed as 330 cubic inches, while both the optional V-8 and the W-31 are 350 cubic inches in displacement.

 

What are the similarities and differences in engine construction (such as cast iron block, overhead valves, hydraulic valve lifters, five main bearings) among the 330 CID and 350 CID V-8 engines from 1964 to 1968?

The 350 CID V-8 was designed with several notable specifications:

• Cast Iron Block: Ensured durability and reliability.
• Displacement: A well-rounded 350 cubic inches.
• Bore and Stroke: Measured at 4.057″ x 3.385″, complemented by five main bearings.
• Compression Ratio: 9.0:1, providing a balanced mix of performance and longevity.
• Power Output: Delivered 325 horsepower at 5400 RPM and 360 lb-ft of torque at 3600 RPM.
• Valvetrain: Overhead valves with hydraulic valve lifters, a proven design for smooth operation.
• Camshaft Specs: Camshaft duration was rated at 250° intake and 264° exhaust, with an overlap of 36°. Valve lift measured 0.435″ on both intake and exhaust sides—attributes that mirrored the legendary W-30 camshaft and underscored its racing influence.
• Carburetor: Rochester 2-barrel on base setups (manual transmission: 7028156; automatic: 7028157; with air conditioning: 7028154).

Significantly, the engine utilized large valves from the big blocks and a camshaft configuration that had already proven its mettle in the racing world, featuring attributes from the revered W-30 camshaft.

The Oldsmobile 330 CID engine underwent several transformations from 1964 to 1967, each variant offering unique specifications catering to different performance needs. Here’s a detailed look at what each year’s models presented:

1964 Variants and Specifications

• Base V-8:
  • Overhead valves, cast iron block
  • Displacement: 330 CID
  • Bore and Stroke: 3.9385″ x 3.385″
  • Five main bearings, hydraulic valve lifters
  • Compression Ratio: 9.0:1
  • Horsepower: 230 HP @ 4400 RPM
  • Torque: 325 lb-ft @ 2400 RPM
  • Camshaft Duration: 250° intake / 264° exhaust, overlap 36°, lift 0.389″ (intake) / 0.390″ (exhaust)
  • Carburetor: Rochester 2-barrel (manual: 7024058; automatic: 7024056; manual w/AC: 7024059; automatic w/AC: 7024057)
• Optional V-8:
  • Overhead valves, cast iron block
  • Displacement: 330 CID
  • Bore and Stroke: 3.9385″ x 3.385″
  • Five main bearings, hydraulic valve lifters
  • Compression Ratio: 9.0:1
  • Horsepower: 290 HP @ 4800 RPM
  • Torque: 355 lb-ft @ 2800 RPM
  • Camshaft Duration: 278° intake / 282° exhaust, overlap 52°, lift 0.433″ (intake/exhaust)
  • Carburetor: Rochester 4-barrel (manual: 7024055; automatic: 702405)
• 442 V-8 (Manual Transmission Only):
  • Overhead valves, cast iron block
  • Displacement: 330 CID
  • Bore and Stroke: 3.9385″ x 3.385″
  • Five main bearings, hydraulic valve lifters
  • Compression Ratio: 10.25:1
  • Horsepower: 310 HP @ 5200 RPM
  • Torque: 355 lb-ft @ 3600 RPM
  • Camshaft Duration: 278° intake / 282° exhaust, overlap 52°, lift 0.433″ (intake/exhaust)
  • Carburetor: Rochester 4-barrel (manual transmission)

1965 Variants and Specifications

• Base V-8:
  • Horsepower: 250 HP
  • Torque: 335 lb-ft
  • Compression Ratio: 9.0:1
  • Carburetor: Rochester 2-barrel
• Optional V-8:
  • Horsepower: 315 HP
  • Torque: 360 lb-ft
  • Compression Ratio: 10.25:1
  • Carburetor: Rochester 4-barrel

1966 Variants and Specifications

• Base V-8:
  • Horsepower: 250 HP
  • Torque: 335 lb-ft
  • Compression Ratio: 9.0:1
  • Carburetor: Rochester 2-barrel
• Optional Low Compression V-8:
  • Horsepower: 310 HP
  • Torque: 340 lb-ft
  • Compression Ratio: 9.0:1
  • Carburetor: Rochester 4-barrel
• Optional High Compression V-8:
  • Horsepower: 320 HP
  • Torque: 360 lb-ft
  • Compression Ratio: 10.25:1
  • Carburetor: Rochester 4-barrel

These detailed technical evolutions—from bore and stroke dimensions to camshaft specs and carburetor options—showcase Oldsmobile’s commitment to refining powerplants for both everyday driving and high-performance needs. Whether you’re combing through build sheets or just admiring the engineering, it’s clear the 330 and 350 CID engines were built to leave a mark, both on the street and at the track.

 

What are the detailed compression ratios for each engine variant?

The 330 CID base and optional engines generally had a 9.0:1 compression ratio, while the high-performance 442 variant was increased to 10.25:1. The 350 CID engines also featured a base 9.0:1 ratio, with select performance variants potentially running higher ratios depending on their specifications.

 

Does every engine have five main bearings and hydraulic valve lifters?

Yes, all listed 330 CID and 350 CID V-8 engines from this period were equipped with five main bearings and hydraulic valve lifters.

 

Are there any changes in construction features (not just performance) across years and variants?

While the fundamental construction (cast iron block, five main bearings, hydraulic lifters, overhead valves) remained consistent, performance variants received upgraded camshaft profiles for increased valve lift and duration, and higher compression pistons in some cases. Carburetor types and specifications also varied to match performance goals and vehicle options.

 

What carburetor models and configurations are used for different transmissions and with/without air conditioning?

Carburetor selection depended on both transmission type and air conditioning. The 330 CID base engine used Rochester 2-barrels, with different model numbers for manual and automatic transmissions, and further differentiation if air conditioning was installed. Optional and performance variants used Rochester 4-barrels, again with distinct model numbers for specific applications (manual, automatic, and A/C).

 

What are the bore and stroke measurements for each engine?

The 330 CID engines used a bore of 3.9385 inches and a stroke of 3.385 inches. The 350 CID engines had a slightly larger bore at 4.057 inches while keeping the same stroke of 3.385 inches.

 

What are the exact camshaft specifications for each engine?

The 330 CID base engine cam had an intake duration of 250 degrees, exhaust of 264 degrees, 36 degrees of overlap, and lift around 0.389-0.390 inches. The optional and 442 variants increased to 278 degrees intake, 282 degrees exhaust, 52 degrees overlap, and 0.433 inches lift on both valves. For the 350 CID base, specs were 250/264 degrees duration, 36 degrees overlap, and 0.435 inches lift.

 

What are the core engine construction features for each 330 CID and 350 CID V-8 variant?

All 330 CID and 350 CID Oldsmobile V-8 engines from this era featured overhead valves, a cast iron block for strength and durability, five main bearings for crankshaft stability, and hydraulic valve lifters for quieter operation and reduced maintenance.

 

What was the significance of Oldsmobile engines in Can-Am and other racing series during the 1960s?

Throughout its production, the 330 CID engine became a flexible powerhouse, adapting to various performance demands with innovations like changing compression ratios and carburetor types. These adjustments helped the engine to stay competitive while meeting different consumer expectations for power and reliability.

During the 1960s, as racing fever swept across the country and new series emerged—especially in organizations like the SCCA—engines like the 330 CID found themselves at the heart of experimentation. Builders matched American V-8s with everything from European chassis to home-built frames, often pushing the boundaries of what was possible with stock blocks. In these scenarios, modifications were seemingly endless, save for certain restrictions on sophisticated aftermarket cylinder heads.

The 330 CID, much like its contemporaries, was subjected to creative reimagining by privateers and mechanics chasing extra horsepower and durability. Compression ratios were tweaked to squeeze out more performance, and carburetor setups were swapped to find that perfect balance between speed and reliability. These kinds of adjustments not only kept the 330 CID relevant on the street but also ensured it could hold its own at the track, adapting to shifting regulations and the ever-increasing appetite for power among racers and enthusiasts alike.

 

Why and how did teams stop using Oldsmobile engines?

When the allowable engine size increased to 6 liters, teams phased out the Oldsmobile block in favor of Chevrolet engines, as the Olds design was no longer optimal under the new displacement limits.

 

How did Oldsmobile engines perform in racing?

The Oldsmobile-powered McLaren proved highly competitive, with Salyer securing pole position at the SCCA National Championship run-offs in Daytona, highlighting the engine’s racing prowess during its tenure.

 

What technical advantages did Oldsmobile engines offer over alternatives?

The Oldsmobile version of the aluminum V-8 was favored in some cases due to its six-bolt head fastener arrangement, offering greater security compared to the five-bolt configuration found on the Buick variant.

 

Who used Oldsmobile engines, and in what cars?

A notable example was privateer Ralph Salyer, who campaigned a McLaren M1A fitted with an Oldsmobile powerplant, a car that also became known as the “Cro-Sal Special” in recognition of Salyer’s partnership with mechanic Gene Crowe.

 

What rules or limitations shaped engine choices in these series?

Engine selection was influenced by regulations that initially capped displacement at 5 liters, later increasing to 6 liters, and mandated the use of production-based blocks with few restrictions aside from barring advanced aftermarket cylinder heads.

 

What racing series were Oldsmobile engines used in during the 1960s?

Oldsmobile engines saw action in the SCCA’s burgeoning sports car series of the 1960s, where American V-8s powered a wide variety of chassis from both professional and home-built origins.

 

What are the camshaft specifications (duration, overlap, lift) for the 330 CID V-8 engines?

During its early years, the 330 CID faced limited availability of performance parts. Nonetheless, engineers and racers found ways to unlock its potential. By 1965, they began experimenting with bigger block heads, taking advantage of key engineering similarities between small and big blocks, particularly in deck height and crankshaft dimensions.

To get more technical, camshaft swaps were a favored experiment. Early cam specs included profiles like Intake 250°, Exhaust 264°, Overlap 36°, with lifts of 0.389″ (intake) and 0.390” (exhaust)—numbers that seem modest by today’s standards, but at the time represented a meaningful bump in breathing room. For those willing to push the envelope, hotter cams boasting Intake 278°, Exhaust 282°, Overlap 52°, and matching lifts of 0.433″ on both intake and exhaust were in circulation, dramatically changing the engine’s character.

However, this modification came with its own set of challenges. The altered configuration led to a notable reduction in low-end torque, which was a critical factor for racing performance. The turning point came in 1967 when Oldsmobile’s engineering team, led by Dale Smith, devised a clever fix: equipping the 330 CID heads with valves from the larger 400 CID engine. This seemingly simple change drastically elevated the engine’s performance, achieving an impressive one horsepower per cubic inch in near-stock conditions, and exceeding 400 horsepower when heavily modified.

In short, the evolution of the 330 CID wasn’t just about bolting on bigger parts—it was a careful dance of duration, lift, and airflow, with each tweak inching the engine closer to its full potential.

 

What is the camshaft lift (intake and exhaust) for the 330 CID V-8 engine?

Intake lift measured 0.389 inches in the standard cam and 0.433 inches in the performance cam; exhaust lift was 0.390 inches standard and also 0.433 inches in the performance variant.

 

What is the camshaft overlap for the 330 CID V-8 engine?

Camshaft overlap was specified as 36 degrees for the standard camshaft and 52 degrees for the performance version.

 

What is the exhaust camshaft duration for the 330 CID V-8 engine?

The exhaust camshaft duration came in options of 264 degrees for the standard configuration and 282 degrees for the performance cam.

 

What is the intake camshaft duration for the 330 CID V-8 engine?

The intake camshaft duration for the 330 CID V-8 engine was available in at least two variations: one at 250 degrees and a higher performance option at 278 degrees.

 

What is the bore and stroke measurement for the 330 CID V-8 engine from 1964 to 1967?

By 1965, they began experimenting with bigger block heads, taking advantage of key engineering similarities between small and big blocks, particularly in deck height and crankshaft dimensions. This tinkering led to a variety of 330 CID V-8 configurations that shared a common backbone—overhead valves, a robust cast iron block, and a bore and stroke of 3.9385″ x 3.385″.

Compression ratios typically sat at 9.0:1 for the base engines, nudging up to 10.25:1 for the high-compression variants. Horsepower ranged from a modest 230 all the way up to 320, with torque figures climbing from 325 to 360 lb-ft, depending on the setup. Hydraulic valve lifters and five main bearings were standard fare, ensuring reliable operation at higher revs.

Camshaft specs varied between the base and optional engines, with durations of 250° intake and 264° exhaust for the milder versions (overlap 36°, lift 0.389″ intake/0.390″ exhaust), and a more aggressive 278° intake and 282° exhaust (overlap 52°, lift 0.433″ both intake and exhaust) for those chasing extra punch.

On the fueling front, Rochester 2-barrel carburetors handled daily duty for the base engines, while the more ambitious options received Rochester 4-barrel units—each with specific part numbers depending on transmission type and whether the car was equipped with air conditioning. This careful evolution of the 330 CID lineup demonstrated a knack for squeezing more power out of familiar hardware, all while keeping the core architecture remarkably consistent.

 

What are the camshaft duration, overlap, and lift for the 330 CID V-8?

Base engine camshafts featured shorter duration (around 250–264°), modest overlap (about 36°), and lifts just under 0.390 inches. High-performance options bumped duration to 278–282°, overlap to 52°, and lift to 0.433 inches on both intake and exhaust.

 

What are the differences between the base and optional versions of the 330 CID V-8?

Optional engines typically offered higher compression, more aggressive camshaft profiles, and a switch from two-barrel to four-barrel carburetors, resulting in significant increases in horsepower and torque over the base versions.

 

How many main bearings does the 330 CID V-8 have?

Every 330 V-8 used a five main bearing bottom end for added durability.

 

What kind of valve lifters and camshaft specifications did the 330 CID V-8 use?

All versions were equipped with hydraulic valve lifters. Camshaft specs varied: base engines had more conservative timing and lift, while optional engines featured longer duration, greater overlap, and higher lift for improved performance.

 

What kind of carburetor was used on each version of the 330 CID V-8?

Base models were paired with Rochester two-barrel carburetors, while the optional variants received Rochester four-barrel setups. Carburetor part numbers differed for manual and automatic transmissions and for air-conditioned cars.

 

What are the horsepower and torque ratings for the 330 CID V-8 engines from 1964 to 1967?

Depending on year and configuration, horsepower ranged from 230 to 320, with torque figures from 325 up to 360 lb-ft. Higher output was found in the optional, high-compression and four-barrel carbureted models.

 

What is the compression ratio for various versions of the 330 CID V-8?

Compression ratios varied by version: most base engines used a 9.0:1 ratio, while optional high-performance variants pushed this up to 10.25:1.

 

What is the bore and stroke measurement for the 330 CID V-8 engine?

The 330 cubic inch V-8 features a bore of just under 4 inches (specifically, 3.9385 inches) and a stroke of 3.385 inches.

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