BAD INFLUENCE – Third-Gen Cummins Puller

Doug Monroe’s Pro Street-Dominating, 24,000-Mile Third-Gen Puller

When it comes to truck pulling, Doug Monroe has just about seen it all. From the days when 600-700hp streetable pullers were still a thing to the mega-horsepower 2.5-inch map groove days to today’s fiercely-competitive smooth bore turbo world, his ’05 Dodge Ram 3500 has run the gamut. Within five years of driving his four-door common-rail off the dealer lot, Doug’s daily-driven, weekend puller was retired from the road and became a full-fledged, purpose-built puller. Now, the Indiana native has an unbelievably clean third-gen with just 24,000 miles on the clock. But more importantly, he’s campaigning one of the most dominant trucks in the 8,000-pound Pro Street Diesel Truck class.

Just because they’re forced to run a 66mm turbo doesn’t mean Pro Street diesel pulling engines don’t make serious power. Doug Monroe’s championship-caliber Cummins is in the 1,100hp range at the crank, and thanks to being built using some of the best parts in the industry he now has four seasons on his 6.7L. A bottom end from Freedom Racing Engines features a girdle, 14mm ARP main studs, Carrillo rods, QSB pistons, and a Hamilton cam. Both the block and head were machined to accommodate fire-rings and 14mm ARP head studs. The competition short-block is topped off with a high-flow Stage 3 head from D&J Precision Machine.

 Track-Tested 6.7L Cummins

Built four years ago, the 6.7L Cummins owes Doug nothing at this point. Still, the proven engine that’s lived its entire life on Amsoil’s Dominator racing oil continues to turn out four-digit horsepower in ultra-reliable fashion. The bottom end was prepped at Freedom Racing Engines, with a girdle and 14mm ARP main studs securing the factory-based crank that swings a set of Carrillo rods attached to QSB pistons. Both the block and head were machined to accept 14mm ARP head studs as well as fire-rings, and a Stage 3 cylinder head from D&J Precision Machine provided a substantial increase in airflow. As we went to press, Doug was on the fence about having the engine cracked open prior to the kick-off of the 2022 pulling season.

As many pullers do these days, Doug sourced his Pro Street 2.6-inch smooth bore turbo from Hart’s Diesel. It’s bolted to a T6 flange Steed Speed exhaust manifold, with 4-inch piping routing exhaust out the 7-inch stack in the hood. Believe it or not, in less than two years’ time this turbo became substantially outdated. “I bought my charger from Harts in early 2020 and by the time I got to Scheid’s that year everyone was already running a different one,” Doug said. But that’s how fast things can change in the ever-competitive world of pulling.

 The Finest Fueling Available

Doug will be the first to admit that being in close contact with the movers and shakers in the diesel industry has its benefits. For him, that means anytime S&S Diesel Motorsport improves its common-rail injector and pump technology he’s privy to try it out on his engine. In his dominant 2021 journey, a pair of S&S’s 10mm stroker CP3’s supported a set of the company’s 400-percent over injectors. Backing up the dual high-pressure fuel pumps is a 250-gph FASS system that never skips a beat. Fine-tuning the injection system is left to Ben Shadday, owner of the lightning-fast, split-window AMSOIL Sponsored Pro Mod Corvette.

A pair of 10mm CP3’s from S&S Diesel Motorsport keep a steady 28,000 to 29,000 psi of rail pressure on tap during the course of a pull. The stroker twins support a set of 5.9L-based, S&S injectors equipped with 400-percent over nozzles. Dialing in the competition fuel system (and the engine as a whole, for that matter) was a task left to Ben Shadday via HP Tuners software.

 66mm Smooth Bore Turbo

In any air-limited pulling class, there is always a mad scramble to have the latest and greatest turbo technology. Things are no different in the category Doug competes in: the smooth bore Pro Street Diesel Truck class. However, somehow Doug has been able to hold off the competition for two whole seasons running a 2.6-inch smooth bore charger he obtained in early 2020. By truck pulling standards, even a year-old turbo can quickly be considered old-tech. Despite this, Doug’s third-gen held its own last year, with the competition just starting to close the gap on him in late 2021. His 2.6-inch smooth bore turbo came from Hart’s Diesel, hangs from a T6 flange Steed Speed manifold, and produces roughly 45-psi of boost going down track.

Thanks to the efficiency provided by the high-flowing cylinder head, boost pressure tops out around 45 psi. After boost has been cooled by the truck’s BD intercooler, it enters the head through a 3.5-inch MEGA intake elbow from Pusher Intakes.

 NV4500, Beefed Up AAM Axles, And A Proven Chassis

While the turbo and injector technology aboard Doug’s Dodge are cutting-edge, the transmission parked behind his Cummins is as old-school (yet proven) as it gets. The venerable NV4500 is equipped with a longer and larger (1-3/8-inch diameter) input shaft, a 4-disc Kenny’s Pulling Parts clutch, and a blowproof bellhousing. The rear AAM 1150 was narrowed at SunFire Off-Road and is fitted with custom axleshafts and a spool, while the factory AAM 925 benefits from Yukon chromoly axle shafts and an ARB air locker. All chassis, suspension, and hitch work was performed at E&M Repair And Fabrication, and Doug is adamant that E&M’s Erik Hucke came up with the perfect recipe for the truck’s always-settled front suspension.

Getting fuel from the factory tank to the CP3’s is taken care of courtesy of a Titanium series lift pump system from FASS. The system can move 250 gallons of fuel per hour and Doug keeps supply pressure between 20-25 psi. Fuel return and supply lines are cleanly routed thanks to a Fleece Performance Engineering fuel distribution block.

 The (Winning) Road Ahead

If you’ve seen Doug’s silver four-door Dodge loaded down with the sled in recent years, you’ve likely seen his truck go the furthest in the dirt. A big win at the 2020 Scheid Diesel Extravaganza, being front-runner at Diesels in Dark Corners, and winning every Battle of the Bluegrass event he went to last year are among his most recent successes. But although he’s regularly in the top three at any given event, Doug will be the first to tell you the road to the front wasn’t quick, or easy. “It was a lot of work, and I got beat a lot in order to get here,” he said. However, now that Doug is one of the most formidable competitors in 2.6 smooth bore, he has a plan for staying at the top. “Turbo and injector technology is the name of the game anymore. You gotta stay on top of it if you want to win.” With plans to go turbo shopping, see what’s new from S&S, and possibly even crack open the engine before summer hits, look for Doug to once again lead the pack in 2022.

The old-school NV4500 is tasked with transferring everything the Cummins dishes out and then sending it through the transfer case. A short list of upgrades performed on the five-speed includes Haisley Machine’s extended length, 1-3/8-inch diameter input shaft and an SFI 6.1 spec blow-proof bell housing. The longer input shaft accommodates a 10-inch, four-disc weighted clutch from Kenny’s Pulling Parts. Hooked to the sled, Doug pulls with 4-Lo selected in the factory NV271 and fourth gear chosen in the NV4500.
Once a dually axle, Doug had the rear AAM 1150’s tubes cut down, fitted with different flanges, and equipped with custom axle shafts at SunFire Off-Road. Behind the Performance Pros cover, the differential sports a spool and 4.56 gears. The factory AAM 925 solid axle still resides up front, but it’s been graced with 4340 chromoly axle shafts from Yukon Gear and Axle, a 4.56 ring and pinion, and an ARB air locker.
E&M Repair And Fabrication’s Erik Hucke handled all of Doug’s chassis work and is a huge reason why the truck pulls so smoothly. The suspension, drawbar, hitch, and sled stops are all of Hucke’s design. Here you can see the hitch, which meets the Pro Street Diesel Truck Class’s 24-inch height requirement, as well as the narrowed AAM 1150.
We weren’t kidding you, the truck literally only has 24,000 miles on the odometer! Soon after Doug bought his ’05 Dodge, it became more of a high-powered weekend truck and a puller rather than a daily driver. By 2007 he was already hauling it to the county fair pulls (in case of breakage), so the miles weren’t exactly being piled on anymore. Of course, once it became a dedicated pulling truck, they all but stopped accumulating.
Street truck or puller? As you’d expect, the low-mile third-gen’s seats are in mint condition. But as you might not have expected to see within the cab of a dedicated puller is a fully intact interior. Over on the driver side A-pillar, DiPricol Optix series analog gauges relay low-pressure fuel supply, boost, and EGT to the driver. Doug keeps tabs on rail pressure courtesy of a 30,000-psi gauge mounted to the steering column.
When Doug made the decision to convert his Ram into a dedicated puller, he also decided that the truck’s signature wheels were staying. His 18×10-inch Weld Sandstorms not only set the third-gen off, but they also make it one of the most recognizable trucks in the Pro Street field. Interco TrXus STS tires, each measuring 35×12.50R18, help the truck take a huge bite out of every track Doug competes on.


The Shell Rotella Truck of the Month, presented by Shell Rotella

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