A 6.6L Cummins Monster Truck Build

AS SEEN IN OUR MARCH 2026 ISSUE – Buy Now!

Cummins powered monster truck

If you don’t find monster trucks cool, I’m sorry. The rest of us will happily enjoy creations such as this that satisfy both our inner child and our craving for carnage. Over the last year I can say we have tried our best to find the most unique and deserving builds to display, and this one fits the bill perfectly. On our recent trip to Useless Truck Meet, we made a quick pit stop at Brandon Overmyer’s shop to check out his Cummins-swapped monster truck. Brandon told us that when he was a kid, his dad owned a monster truck but sold it before Brandon ever got the chance to drive it. While he went on to build a career in diesel motorsports, Brandon never lost his love for monster trucks, so he decided to mash the two together.

Brandon tracked down the perfect starter kit: a 2001 monster truck out of Portland, Indiana, built by a guy who was running eight monster trucks at once back in the day.  It had a custom square tube frame, a fiberglass body, humongous tires, and a single center-mounted race seat. American Outlaw was its name, and it came with a big-block Chevy that needed to go. Naturally, Brandon chose a 12V Cummins in lieu of the BBC. Custom mounts were made for both the 48RE transmission and the engine along the square tube frame. The Cummins was bored out to 6.6L, so this one will sound a little bit crankier and will snarl that much more.

Some of the mods done to the engine are Wagler rods, a Hamilton camshaft, a Hamilton Warhead, ARP head studs, as well as a Stainless Diesel manifold and billet ball bearing S475 turbo. The 48RE has all billet shafts, a constant pressure valve body, a SunCoast Stubby Shaft kit, and is mated to a Profab drop box transfer case along with a Goerend torque converter. If you would like a more intimate look at the build process, be sure to head over to Brandon’s YouTube (@Merica-TV) to check out the many videos he has on the build and what he currently does with the truck. Spoiler alert: it’s pretty cool. Brandon doesn’t gatekeep his thought process, nor does he shy away from explaining why he chose certain parts. Brandon explains in one of the videos that he went with the S475 over a compound setup because it would be easier to keep the single spooled and in the power band while competing/ripping around various tracks and layouts. To some, that makes total sense. To aspiring builders and newcomers to the scene, that is valuable knowledge to digest and make note of.

This truck doesn’t just sit around. Brandon wheeled it out to let us see what it’s capable of just in the back of the shop. No, we didn’t get the chance to have it crush our rental, but rest assured, Brandon absolutely sends it off jumps and crushes vehicles at every Full Throttle Monster Truck event he can make it to. How else would you think he knows where the tires rub on the fenders after a 30+-foot jump? The EPI quad shocks do the equivalent work of 10,000 elephants to catch the huge weight of the Cummins and everything else once it’s slamming back down to earth. Knowing the truck gets driven like that is also a testament to the fabrication Brandon and his team did. The 66x43R25 tires weigh up to 1,000 pounds each and towered over us. Getting pictures of the interior and gauges was a pipe dream for someone vertically challenged. I had to pass the camera off to Diesel World editor, Tucker Harris, to get those photos. It’s difficult to fully appreciate how much engineering goes into making these trucks operate day to day. For instance, the truck was on hold until the slip yoke kit for the transmission came in; otherwise, the transmission would sit at an angle that would break if it ran without it.

Brandon told us that he intends on continuing with this truck for as long as he can. Race, break, build, repeat is the motto. Of course, this build wasn’t a walk in the park, but nothing worth doing is easy, and you won’t know if you can achieve something if you never try. It’s not every day that you get to say you run the only active diesel monster truck in the United States. Keep your eyes peeled if you live in Indiana or the surrounding area, as you may be able to catch the bored-out Cummins grunt at your next local monster truck event. And trust us, Brandon loves to rip this thing, so there’s a good chance you’ll see it!

Ram 2500 Monster Truck

Engine  

• 1994-’98 5.9L Cummins bored to 6.6L
• Stainless Diesel billet ball bearing S475 turbo
• 5×25 Scheid injectors
• Kenny’s Pulling Parts billet timing case
• Hamilton Warhead
• Hamilton 188/220 camshaft
• SMT Performance billet roller rocker system
• ARP 625 head studs
• Pure Diesel Power intake manifold
• Stainless Diesel headers
• 48RE transmission
• Firepunk Anteater standalone controller
• SunCoast Stubby Shaft kit
• 1480 U-joints
• Constant pressure valve body
• All billet shafts
• Goerend 17-250 torque converter
• Profab drop box transfer case
• Custom two-piece rear driveshaft

Photos by Mach 1 Media