Firepunk has found better ways to harness massive torque, for either street or strip.

The smoke and throaty rumble that emerge from a diesel truck attest to the brutal struggle of physics that’s taking place beneath its hood, as pressure and heat turn an otherwise docile fuel into something explosive. Managing the power and torque, and harnessing it, are crucial for a diesel truck, whether it spends its working life hauling a trailer up long, steep grades or arrowing down the quarter mile, aiming for an elapsed time that might shock those unfamiliar with diesel drag racing.
From very obscure beginnings that usually involved modified Class 8 highway trucks, the universe of diesel drag racing is now a dream world where actual working trucks—many of them still street legal—routinely blast out four-digit horsepower totals with great gobs of torque that could seemingly twist the Earth on its axis. Like all forms of straight-line competition, diesel dragging involves connecting copious power to the ground efficiently, a consideration that’s also germane to heavy towing.

Optimizing that make-or-break connection between power and pavement is the mission of Firepunk, which specializes in prepping the drivelines of big-output diesels by its building of super-hardened automatic transmissions, along with offering engine parts for big compression-ignition monsters from Ram, General Motors, and Ford.
Firepunk’s heritage goes all the way back to when its founder, Lavon Miller, was tinkering with oil-burning work trucks inside his family’s dairy barn in Plain City, Ohio, where Firepunk Diesel began and has been based since its founding. It was a gradual process that began when Miller pieced together his first pure drag truck in 2008. Since then, the firm’s reputation has grown to where it’s one of the industry’s leading builders and suppliers of ultra-duty automatic transmissions and specialty swaps where really hot trucks are created. Firepunk built its name by scoring victories at top diesel performance drag races during its formative years, which put it on the map for customers in this highly specialized segment of motorsports.
As Miller explained, the founding principles at Firepunk Diesel go all the way back to employing trial and error to add horsepower to his own truck. “Diesels for me started because I had a concrete business, and I needed a truck that was going to help me do a workingman’s job,” he recalled. “So I bought a diesel truck in my teenage years when I was about 19. Boys being boys, they’ll pick up forums and find out that there are ways where you can increase horsepower, and that made a pretty significant impact in my young brain, how you can just put a tuner on a truck, and you pick up 120 horsepower and 250 foot-pounds of torque just by plugging in a module. Now you’ve gone from a work truck to a hot rod.”

Firepunk, today, has the capability to muscle up a lot of trucks. The firm’s core mission is hardened automatic transmissions, but the firm’s selection of products is far broader than that. For example, Firepunk divides its available components for Ram pickups by the generation of the truck, with the catalog further specifying the parts according to the displacement of the truck’s Cummins diesel engine. The total comes to thousands of pieces, ranging from transmission valve bodies to traction bars, performance filtering systems, and a variety of high-capacity turbochargers, one of them being a Tater Built bolt-on unit for Ram 5.7 diesel applications. Add in the add-ons for Duramax- and Power Stroke-powered pickups from GM and Ford, respectively, and Firepunk’s parts inventory grows exponentially.

From Concrete to Trucks

The firm grew, literally, from a single modified pickup that set Miller on his journey to build a business, in large part thanks to word of mouth, and social media, that proclaimed to the diesel performance world what the company could accomplish.
“Things got carried away really quickly for me,” he explained. “In rural central Ohio, my father was a farmer, my grandfather was a farmer, and we were country boys with welders and a shop and tools, so I started tinkering. I bought my first truck in 2004, a 2001 Dodge Ram 2500, and had the transmission in it torn up by June. So then I bought a new, built transmission, a tuner, bigger injectors, and working with my friends, I fabricated a whole twin-turbo system. That meant I blew a head gasket, because there was more boost, so I pulled the head, O-ringed it, and went from there. From about 2004 to 2009, this was a 100% hobby for me.”
At the time, Miller had a contracting business doing decorative concrete work on residential properties in central Ohio, an endeavor that took a major hit following the 2008 banking crisis. “When the housing market collapsed, I did a big home-and-garden show in Columbus in the spring and got no leads. But during the winter and on rainy days, I had still been helping friends on trucks, doing turbos, so I really switched from doing concrete to trucks without a business plan. I was doing just trucks by 2010, full time. I knew how to fix transmissions, and people were sending me trucks after hearing about us from the diesel forums and on social media.”

The big jump to national prominence came when a Firepunk customer, Damon Wisley, took a Firepunk-modified Ram pickup to a major challenge hosted outside of Denver in 2013 by Diesel Power magazine, which involved not only drag racing but also a dyno challenge, a 1/8th-mile drag race while towing a 10,000-pound trailer, a 100-mile ride across the Rockies to determine average fuel economy, a sled pull, and an obstacle course negotiated while pulling a trailer loaded with a Bobcat excavator.
Miller recalled, “Damon brought me a truck, a 2004 Ram, and we did a pretty big build, about 1,200 to 1,300 horsepower, and took it to Denver, running against the best of the best, which kind of put our name on the map. We went back in 2014 and dominated that competition, and then defended it again in 2015, and that was really the start of our nationwide publicity. Since then, we learned that you can only win that event twice, and that we were the first ones to win it back-to-back.”
The next leap forward came when another periodical, Diesel magazine, organized an invitation-only contest called the Ultimate Callout Challenge, involving 30 modified trucks. “The basic rule was that it had to be a truck, minimum 4,500 pounds,” Miller said. “We took a 2006 regular-cab truck and added structural supports so it could run at up to 8,500 pounds, like a Swiss army knife. We went and won 2016, 2017, and 2018. Here we were, country bumpkins, trying to put our heads together, going against $50 million companies. For five years, in pretty much every such challenge, we were able to go out and dominate the industry.”

Core Business

Though its inventory includes scores of parts aimed at upgrading diesel engines from various manufacturers, Firepunk is not in the engine-building business. The firm’s core business is modifying and selling severe-service automatic transmissions from all manufacturers. As an example, one popular swap allows buyers to acquire a fully Firepunk-hardened Chrysler swap kit that allows racers to exchange the often-indecisive shifting of the 68RFE transmission to a more predictable 48RE, with complete hardware, mounting accessories, fluid lines, and bellhousing adapters. Firepunk also produces a line of heavily modified Allison transmissions for mating to Duramax diesels, especially the A900 and A750 transmissions.
“In the early years, in the Diesel Power days, I built my own engines,” Miller said. “I quickly realized that I had to go to a machine shop, machine the block, hone it, and then I’d come back and start assembling it. Well, if my bearing clearances aren’t perfect, or the piston walls aren’t perfect, I’ve got to pack it all back up, take it back to the machine shop, and machine it again. So I’ve built a relationship with D&J Precision Machine, about an hour and a half from us in Cambridge, Ohio, and they’ve got all the CNC machines, the hones, plus I have them do all my engine builds, top to bottom. We’re a dealer for them, and they do the same core manufacturing process we do with our transmissions, only with the engines.”

Firepunk now has 25 employees who serve a genuinely national customer base. Most were recruited locally. Miller has a winning strategy of identifying potential Firepunk staffers by hosting field trips for students from regional vocational schools. Occasionally, the selection process is more informal than that: “The attraction of racing and performance adds a level of desire to work at Firepunk. People want to be a part of it,” Miller said. “One of my lead transmission guys I recruited from a local pizza shop where we would go to lunch. We’d see the guy there and we could see that he was busting his tail, he took the initiative, he would do everything in his power to make sure we got our food fast so we could be back in time from our lunch break. I saw his work ethic, and I realized if he had that core work ethic, then I could teach him the job skills. We did that, and 10 years later, he’s one of the lead guys in our transmission department.”
Racers, too, are key to spreading the Firepunk mantra. One of them is Robby Garcia of Fort Worth, Texas, who holds Firepunk’s long-distance record by transiting his fourth-generation Ram all the way to Ohio for work, led by the aforementioned 48RE transmission swap. “It’s a stronger transmission that will hold up to the power these trucks can make,” Garcia said. “I made 2,147 horsepower on Firepunk’s dyno last year, and expect to make 2,400 to 2,500 this year, and it’s still actually street legal. Man, they are hands down an amazing shop to work with. Even at the races, anytime you need help with something, they’ll always hop right over. They’ve done work for me from transmission to engine swaps to nitrous, and they helped me take it to the next level.”
James Weaver is another Firepunk customer, who hails from closer to home in Troy, Ohio. He also did the popular transmission changeout with his fourth-generation Ram, noting that “it’s easy to get horsepower, just add more fuel. The thing that Lavon did that made the truck so reliable was the transmission. I went from the standard six-speed to the 48 swap, an older four-speed transmission, so being able to reliably drive around in a truck with 800 horsepower while you’re pulling a trailer is pretty cool. They’re the best in the industry at what they do.”
Miller explained that since the business world is subject to unforeseen change, he’s transitioning to a new LLC that will see the company rebranded as simply Firepunk, no “Diesel.” As he laid out the plan, Miller said, “That’s mostly so we can keep our heads on a swivel, so if the EPA and state regulation keeps cracking down on diesel performance, where we can’t defeat any emissions systems or remove systems, they hold our feet to the fire over that, I can shift my business into other avenues, like if I had to shift into more service- or fleet-oriented use in the shop as opposed to performance.
“The fabrications and race departments can stay race,” he said. “That’s for non-highway use, and I want to do the big custom-build marketing and exposure, but I want to grow the manufacturing side, with race-type parts we now manufacture like a valve cover lifter, which helps you get hold of the cover and lift it off the engine. We made them for convenience for our techs, and now we’re probably selling 25 to 30 of them a month. There are probably 50 products that we manufacture and powder coat here. I want to keep growing the manufacturing side of our race department.”