OUT OF RETIREMENT - Diesel World

A BARN-FIND CHEVY C30 WITH A SECOND-GEN CUMMINS, CHASSIS, AND AXLES

You don’t have to look very hard to find fans of Chevrolet’s iconic ’67-’72 trucks, but if you’re lucky enough to bump into Jeff McCord—owner of LinCo Diesel Performance and someone who knows his way around diesel swaps—you’ll find a one-of-a-kind ’68 parked in his stable. It’s not the familiar 10-series, but in deciding to convert a C30 1-ton into a four-wheel drive, Cummins-powered workhorse, Jeff has built something truly unique. Thanks to having a P-pumped 5.9L take-out engine, an NV4500, and an entire ’95 Dodge dually to pull parts from, it’s no wonder the project unfolded the way it did.

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A TRUE BARN FIND

When Jeff first spotted the C30 abandoned in a barn back in 2014, it had long-been retired from its days of hauling building materials for a St. Louis area construction company. Unfortunately, the truck’s rockers had been resting on the shelter’s dirt floor for some time, rendering them (and much of the rest of the cab) irreparable. However, after sourcing a salvageable ’72 model year cab all was forgotten, and luckily the original doors , fenders, grille, and front bumper were all attainable.

LESS IS MORE

As a C-series enthusiast in virtually every way, Jeff held true to his belief that the truck should remain as era-specific as possible. That meant the original body panels were treated to Scotch-Brite and clear coat rather than a full-on paint job. The Cummins’ valve covers were bead blasted and the intercooler piping left raw rather than shot with flashy paint or powder coating. And finally, for a bit of character as well as a glimpse in to the truck’s workhorse past, even the arm wear at the top of the driver side door was left alone.

EASY-BREATHING 12-VALVE

Humming away when it was pulled from the rusty, ’94 Dodge 2500 it was powering, the 240,000-mile 5.9L Cummins was in need of nothing when the engine swap was performed. However, with plans to make more than 400 -rwhp and spin the 6BT as high as 4,000 rpm, Jeff added 60 -lb PacBrake valvesprings for good measure. Then, to keep the factory freeze plugs from blowing out of the block at elevated engine speed, a set of T-Rex billet boltin freeze plugs got the call. On the induction side , an HX35 fitted with a 63.5mm inducer compressor wheel bolts to the factory exhaust manifold and builds more than 30 -psi of boost. A Vibrant Performance intercooler drops intake temps and EGT, while a Banks Twin-Ram intake manifold sits in place of the restrictive factory cast piece.

MASSAGING THE P-PUMP

The key to nearly tripling the 12-valve’s factory power output called for all the usual P7100 tweaks. Power Driven Diesel’s 4,000-rpm governor springs, 025 delivery valves, and AFC Live with a max travel kit are all employed, along with a custom-ground #0 fuel plate, an adjustable overflow valve from Tork Teknology for improved supply pressure, and an 18-degree bump in timing. The factory injectors were left alone, but a fresh mechanical lift pump from Cummins replaced the 20 -year-old original.

NV4500 & NP241

Utilizing a second-gen frame made the integration of both the engine and transmission as straightforward as possible. Like the Cummins, the NV4500 is hard to beat in terms of durability and how much torque input it can tolerate. The five-speed hand-shaker was pulled from the ’94 Dodge that donated the engine, as well as the NP241 transfer case that was married to it. Believe it or not, a budget-friendly, heavy-duty clutch from Jeff’s local Napa Auto Parts handles the low-end grunt of the 5.9L at the present time.

SECOND-GEN FRAME, AXLES, AND SUSPENSION

Even though a one-foot section had to be chopped off of the second-gen, Quad Cab-intended frame, swapping the C30 body on to the Dodge chassis made the most sense. After all, the 3500 4×4 model donor came with a Dana 60 front axle and the near-bulletproof Dana 80 in the rear—not to mention the fact that the coil spring front suspension was already designed for the weight of the Cummins. A homemade hydro boost system incorporates parts from a ’97 Dodge, the power steering pump off of a bread van, and a reservoir from a Super Duty.

READY FOR ANOTHER 50 YEARS

In passing, most people don’t recognize the fact that Jeff’s C30 is four-wheel drive or that it’s all-Dodge underneath. However, anyone within earshot of the Cummins’ rattle is immediately aware that something about this old Chevy is unique—and we can only imagine the looks it gets at the filling station, when the cap for the factory behind-the-seat gas tank comes off and the green nozzle slides in. From the hand-painted lettering on the doors to the clear-coated original paint to the million-mile powertrain, Jeff definitely transformed this neglected barn-find into something special. Whether it’s used for work, leisure, or both, the truck’s next half-century could easily be more productive than its first.

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Hanging off the factory exhaust manifold you’ll find a Holset HX35, but it isn’t just any HX35. Machined to accept a billet, 63.5mm compressor wheel, this version moves quite a bit more air than the factory one, and builds more than 30 psi of boost at full tilt. Exhaust gases are freed up thanks to a 4-inch stainless system that was originally intended for a ’94-’02 Dodge. Only the tailpipe section had to be modified to work on the C30.

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No stranger to tractors, heavy equipment, and especially second-gen Dodges, Jeff knew how to get the most out of the factory 175hp Bosch P7100. First and foremost, he replaced the rusted out delivery valve holders with brand-new Bosch units, followed by Power Driven Diesel’s 025 delivery valves, its 4,000-rpm governor spring kit, and a customground #0 fuel plate. Beyond that, timing was advanced to 18 degrees, a Tork Teknology adjustable overflow valve was added, and the original Cummins lift pump was also replaced with a fresh one.

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Although Jeff McCord’s Chevrolet C30 left the factory packing an inline-six, the 359 ci 5.9L Cummins is a tad bit more powerful than the former 292 ci gas job. Yanked from a ’94 ¾-ton Ram plow truck, the only internal upgrades the quarter-million-mile P-pumped Cummins has seen is a set of PacBrake 60-lb valve springs in the head and T-Rex billet bolt-in freeze plugs in the block. The motor mount brackets were also relocated four inches closer to the C30 cab’s firewall.

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Thanks to the ’95 dually, it wasn’t just the frame that was donated to the build: Jeff’s C30 got the stout, coil-sprung Dana 60 solid axle up front and the time-tested, leaf-sprung Dana 80 in the rear. Both sport 3.73:1 gears. If you look closely at the license plate mounted to the original front bumper, you can see an “85” in the middle of it. This denotes the year 1985—the last time the truck was registered. That’s right, it’d been sitting in a barn for nearly 30 years before Jeff crossed paths with it.

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With a hole left behind from the truck’s original transmission, Jeff decided to use it to mount a one-of-a-kind cup holder he’d been wanting to fab up for some time. The unique creation repurposes 3306 Caterpillar rods and two 6BT pushrods—and it does a fine job of securing a pair of road sodas.

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Measuring, cutting, fabricating, wrenching, sourcing parts, and an unavoidable amount of body work all take time. More than five years in the making, it was only fitting for Jeff to grace the hood with this little catchphrase (hand-painted, no less).

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Surprised to find a Banks Twin-Ram intake manifold on the ’94 Cummins, and knowing how restrictive the factory intake manifold is on the 12-valve, Jeff gladly left the high-flow piece in place during the engine swap. An oldie but a goodie, Banks’ dual inlet manifold provides two points of entry on the intake shelf, eliminating internal hot spots and equalizing airflow into each cylinder.

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In-cab fuel control is made possible courtesy of Power Driven Diesel’s AFC Live, complete with the company’s 30-35 psi max travel kit. Thanks to this ground-breaking product, Jeff is able to adjust max fueling and fuel rate from the driver seat on the fly, as well as get instant full fueling with the flick of an override switch. Here, you can see that the AFC Live module is coupled to a trailer brake controller, which believe it or not, will see use.

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The headache rack, steel flat bed, and gooseneck hitch all scream work—and thanks to being built around the use of a second-gen frame, axles, and suspension, Jeff’s C30 creation is ready for any task. Before the cab could be set and the flat bed attached, roughly one foot was chopped off the Dodge frame, which was originally intended for a Quad Cab model Ram.

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Because a complete chassis and powertrain swap made the most sense for a truck that would be used for work, the NV4500 and NP241 transfer case were robbed from the same ’94 Ram 2500 that donated its engine to the cause. A 13-inch, heavy-duty replacement clutch from Napa transfers power from the engine to the tried and true five-speed, and ’99 model year hydraulics are also part of the equation.

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The rest of the interior is primarily original, and superbly clean given its age. A pair of GS series gauges from Auto Meter sit on the dash (one for boost, the other for EGT), and a brand-new fuel tank sits in the factory location behind the seat.

1968 CHEVROLET C30

OWNER: Jeff McCord
HOMETOWN: Silex, Missouri
ODOMETER: 105,000 miles (truck), 250,000 miles (engine)
ENGINE: 5.9L Cummins 12-valve with 60-lb PacBrake valve springs and T-Rex billet bolt-in freeze plugs
FUEL: Factory 175hp P7100 with Power Driven Diesel 4,000-rpm governor springs, 025 delivery valves, new Bosch delivery valve holders, AFC Live with Max Travel Kit, custom-ground #0 fuel plate, Tork Teknology adjustable overflow valve, 18 degrees of timing, OEM Cummins mechanical lift pump, stock injectors
AIR: Holset HX35 with 63.5mm compressor wheel upgrade, Banks Twin-Ram intake manifold, Vibrant Performance universal intercooler, Derale Performance dual electric engine fans
EXHAUST: Factory manifold, customized second-gen 4-inch stainless steel turbo-back system
TRANSMISSION: NV4500 manual (’94 take-out) with Napa heavy-duty 13-inch clutch, NP241DHD transfer case, custom rear driveshaft
HORSEPOWER: 450 hp (est. dyno)
TORQUE: 850 lb-ft (est. dyno)
TIRES: 235/85R16 Achilles Desert Hawk X-MT
WHEELS: 16×6 factory steel
SUSPENSION/STEERING: 1995 Dodge 3500 front coil spring, rear leaf springs, custom hydro boost power steering and brake conversion
AXLES: Front Dana 60, rear Dana 80, 3.73 ring and pinion