This Dodge Ram Dually Features 6.7L Cummins Swap and 1,127 HP

1,000 hp & Counting

At Michiana Auto Mania 2025, we met with Cory Dixon and Gary, his lovingly named third-gen Dodge Ram dually. Why Gary, you ask? Well, when Cory did his first manual swap into the truck, the shift knob had Gary from SpongeBob on it with a big old turbo for his shell. Naturally, Gary just fit and has since remained. If you know Cory and his wife, Chelsey, then you know Gary. One might think they’re referencing a grandpa or an uncle whenever brought up in a random conversation, but nope, it’s just a 2004 Dodge that happens to make 1,000+ hp. That’s right—this big single turbo Cummins has gone through a ton of work to land here and put Cory in four-digit horsepower territory.

Cory picked up this truck in 2021 and has done the majority, if not all, of the work himself. From yanking out the auto transmission and throwing in an NV5600 and then going back to an auto with an FMVB setup to pulling the 5.9L motor and swapping in a 6.7L engine, even converting the single-wheel rearend to a dually, this truck has had some serious attention given to it.

After throwing down an insane 1,127 hp on Blessed Performance’s dyno at Michiana, we can all agree that Cory’s hard work paid off. The truck started off as a 5.9L Cummins with an automatic transmission, with the NV5600 manual transmission swap happening first, then came the 6.7L Cummins swap. Cory ended up using the ECM and all of the wiring from the 5.9L and was also able to utilize the injectors because in 2003, the 5.9L injectors shared the same spray pattern that you would find in a 6.7L piston bowl. You can find a VS Racing 80mm turbo, an S&S 14mm CP3 pump, ARP 625 head studs, Manton push rods, and a FASS 260 gph system on the 6.7L, just to name a few mods. This setup was not all sunshine and daisies, as tuning the 2003-’05 ECMs were finicky and difficult to nail down tune-wise.

After working with multiple tuners trying to get it to run happily to no avail, Cory posted on the Firepunk Facebook group as a last-ditch effort for guidance, and lo and behold, some feller from Quebec asked Cory to give him a chance. This gentleman ended up solving all of the quirks, and to Cory’s relief, got the truck running great. A huge shoutout goes to the community that Firepunk has created. They have some of the smartest and friendliest people in the entire industry in their corner, and we are thankful for the shared wisdom they have made available to those who seek it.

“What does FMVB mean? Full Manual Valve Body. It’s a modified automatic valve body that allows you to retain control over gear selection by removing the electronic shift logic, even in an automatic transmission, effectively making it a manual once paired with the proper shifting setup. Shifts are instant and raw, giving you full control of power delivery.”

Having achieved his goal of 1,000+ hp, Cory told us that after all of his hard work, he still wants more horsepower. That sounds about right. Once you get a taste, it’s hard to put it down.

Here at Diesel World, we are quite good at identifying diesel horsepower addicts, so if you believe you or someone you know may have an addiction to horsepower, please send us an email so we can see what crazy build started the addiction. Who knows what this truck may throw down on the dyno this year, but we’re excited to find out, and we will, of course, update everyone on our socials!