The potent Cummins under the hood made over 2,200 horsepower on the SuperFlow chassis dyno at the Ultimate Callout Challenge in Salt Lake City.

Lavon Miller is the 31-year-old owner of Firepunk Diesel, the highly successful diesel performance shop out of Plain City, Ohio. After winning a large diesel invitational competition two years running in 2014 and 2015, there seemed to be little that could stop the Firepunk dominance on the dragstrip or in cumulative competition. Then something new came along in 2016 in the form of the Ultimate Callout Challenge—a three-day torture test of truck and team on the dyno, drag strip, and sled pull.

Miller and his team wanted to prove that their previous racing and competition efforts were no fluke so they accepted the invitation to compete. But rather than compete with the previous truck, they wanted a new, purpose-built racer to run at the UCC and use it to compete in the Pro Street drag racing class.

Dedicated Race Truck

Late in October of 2015, Miller found a 4WD standard cab 2006 Dodge Ram 2500 with over 240,000 miles on it at a dealer in Oklahoma. Within a few days the Firepunk Diesel team had the truck stripped down to the bare cab and chassis under the direction of Miller’s older brother Lyn, who is also the Crew Chief and Lead Fabricator on the project.

Like looking down the barrels of a shotgun: You know these two large Engineered Turbo S400 based chargers are here to do some serious work. You can also see the manifold charger nestled in below the pair of atmosphere chargers.
The machined billet aluminum valve cover emblazoned with the “ENFORCER” name is proudly displayed atop the engine.

The new build would be a dedicated race truck so the crew did everything possible to reduce its weight, aiming for the ODSS Pro Street Class minimum weight of 4,500 pounds. While many small areas were addressed for weight savings, a couple big ones made the most impact on the scales. Removing the rear section of the frame and replacing it with custom fabricated tubular chassis elements of 1-5/8” chromoly removed a huge amount of weight. All told, the weight savings paid off with the truck tipping the scale at a svelte 4,590 pounds without the driver.

6.7L Cummins

The Firepunk team worked with Drew Pumphrey at D&J Precision Machine to build a new Enforcer 6.7L Cummins engine. They started with a stock Cummins 6.7L block that was machined to accept a deck plate and iron cylinder sleeves for additional strength and to make future servicing easier. A Cummins 6.7L crank spins in the center of the block, swinging around a set of D&J Precision Machine X-Beam billet rods with one inch of additional length; these are capped with a set of D&J FSR (Forged Steel Ring) billet pistons. ARP main studs keep the crank and rotating assembly secure at the heart of the engine. The block also holds a Hamilton Cams roller camshaft to quickly open and close the valves even at the high RPMs seen when drag racing. A factory Cummins oil pan and oil pump provide lubrication for the monster motor.

Looking in through the lightweight GTS fiberglass passenger side door you can see the clean wiring and control panel mounted against the firewall, as well as the TCI Automotive shifter and quick-release fire extinguisher at the ready.
Lyn Miller fabricated the back-half chassis with plenty of adjustment available for the team to dial the truck in for various track conditions, including sled pulling as required for UCC-type events.
The potent Cummins under the hood made over 2,200 horsepower on the SuperFlow chassis dyno at the Ultimate Callout Challenge in Salt Lake City.

The block is capped with a factory Cummins head that has been treated to 5-axis CNC porting and Stage 3 machine work by the crew at D&J, along with the deck plate that is all held firmly in place with a set of custom 9/16” ARP head studs. D&J stage 3 7/16” chromoly push rods actuate the valves. The head’s factory intake shelf was removed and replaced with a D&J Precision billet aluminum machined manifold and intake ram to get plenty of air into the engine and distributed to the cylinders evenly to make tons of power. The valves are controlled with 115- pound springs and held securely in place with titanium retainers.


The Firepunk team built a triple-turbo compound setup using three Engineered Turbo S400 BorgWarner turbochargers. A Stainless Diesel stainless steel T6 exhaust manifold flows the spent gasses into the manifold charger, which then hands the gasses off to the pair of atmosphere turbos through custom-fabricated stainless steel hot pipes that the Firepunk team built. From the atmosphere chargers, the spent gasses are channeled through 90-degree bends and up to the open air through short hood stacks.

Peaking under the rear you can see the sump in the fuel cell as well as the AAM 11.5 rear axle and easy-to-service G2 cast aluminum differential cover.
Miller and the Firepunk team replaced the factory 3/4-ton brakes with lightweight TBM convoluted rotors and 4-piston calipers for better stopping power in a lighter package.
Looking at the truck from the rear you can easily see a large portion of the weight savings efforts with the frame and bed removed from behind the cab and replaced with chromoly tubing and GTS fiberglass bedsides. You can also see the Afco coil-over shocks used to dial in the truck’s launch and dual Stroud parachutes.

On the intake side of the turbo system, the pair of atmosphere turbos draws huge amounts air into the compressors and passes it along to the manifold charger mounted directly below the pair. After the second stage of compression, the intake charge is channeled through a reinforced Hogan intercooler to reduce the intake temperature. The Firepunk team fabricated custom stainless steel inlet and outlet piping with bellows to handle the pressure and movement while channeling the intake charge from the Engineered turbos to the intercooler and back out of the intercooler to the D&J intake manifold.


To provide the needed fuel for the engine, Miller and crew turned to Exergy Performance to meet their demands. A single Aeromotive 360 fuel pump and filter system sends fuel from the aluminum fuel cell, mounted in the rear of the chassis, up to a D&J fuel distribution manifold that hands fuel off to a trio of high pressure Exergy 12mm stroker CP3 pumps controlled by a Wehrli Custom Fab control module. High pressure fuel from the CP3s is fed into fuel rails before going to individual Exergy 500%-over fuel injectors to deliver massive amounts of fuel to each cylinder.


Miller and his team control the engine through EFILive tuning to optimize its performance. Firepunk turned to the pros at Spaghetti Menders for wire harnessing and electrical distribution. They installed the modules on an aluminum plate mounted along the firewall on the passenger side of the cab to make the truck easy to work on and trouble shoot. To data log and monitor the truck’s performance, Miller also integrated a Microsoft Surface tablet mounted securely to the main dash crossbar of the roll cage. While competing at the 2016 Ultimate Callout Challenge the truck put down 2,211 horsepower and 3,309 lb-ft of torque; the best chassis dyno numbers they have recorded to date are 2,348 hp and 4,002 lb-ft.


Putting all that power to the ground requires a stout transmission and that’s how Firepunk builds them. They used their Competition Stage 3 transmission package to back the potent Cummins engine. A billet SFI-rated flexplate is bolted and safety wired to the crankshaft with ARP bolts. It is connected to the transmission through a Diesel Performance Converters 2,600rpm stall quad-disk billet torque converter to pass the power to the FPC3 “Golden Nugget” transmission. Internally, the transmission uses billet shafts throughout to safely handle the high power and high stress. Gear selection is handled by a TCI Automotive Outlaw shifter with an electric Shiftnoid to actuate shifts from a push button on the steering wheel.


Double-adjustable Afco coil-over shocks are used on all four corners of the truck for weight savings and to allow Miller and his team to adjust the truck for various track conditions. The rear suspension uses custom ladder bars and a track bar to keep the axle in position. The front retains the double control arms and track bar, but the factory components were replaced with stronger fabricated chromoly bars with Steinjager rod ends for strength and adjustability. The steering system was also upgraded with Synergy chromoly tie rods and track bar to keep the truck straight and true when Miller hammers on the loud pedal. Braking chores are handled by TBM Brakes with their rigid 4-piston F4 calipers and Revolution convoluted rotors at all four corners to slow the truck down from 170mph speeds safely at the far end of the track.

The massive Pro Street build was completed in just five months, allowing the Firepunk team to get the truck on the track for some test passes before heading west to Utah for the Ultimate Callout Challenge in May 2016. The spring 2016 Rudy’s event was its first public unveiling, and it was a huge success with Miller and the truck making it to the semifinals on its first passes down a drag strip. The next weekend they tested the truck for the first time on a quarter-mile strip and put down an 8.27-second pass at 166 mph, backing that up with an 8.49-second pass at 169 mph to give the Firepunk team the confidence they needed to go out West with guns blazing. At the UCC, Miller took second in the dyno competition, first in the drag race, and second in the sled pull, giving him the overall win and distinction as the winner of the inaugural Ultimate Callout Challenge. Since that event they have continued to do well during the truck’s debut season by taking the 2016 ODSS Pro Street Class Championship. DW


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