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Diesel of the Week

Iron Rod – a 1947 Federal with Dual Cummins Engines

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Something we see a lot of in the diesel community are custom-built trucks. These one-off creations are typically dedicated to a specific person or application, and often represent important life events. These symbolic builds personify the truck and give it more character than your average run-of-the-mill machine.

Enter Steve Darnell and his truck named “Iron Rod.” The 1947 Federal looks like it came through a time machine, especially next to all of the other modern diesel machines we saw at the Ultimate Callout Challenge this year. Iron Rod is special, not only for aesthetics, but also for the fact that it boasts not one, but two powerful Cummins engines. One powers the truck, and the other powers a Lincoln SA200 welder mounted to the bed of the vehicle.

Darnell is the owner of WelderUp, a complete, custom fabrication shop specializing in one-of-a-kind vehicles located in Las Vegas. He also stars in the popular TV reality series Vegas Rat Rods on the Discovery channel, which details the WelderUp crew’s escapades and awesome builds.

Growing up in the steel industry and being an iron worker for 12 years prior to focusing on welding, Darnell learned all there is to know about metalwork, and it became an important part of his life. When the opportunity came, he knew he wanted to build something that represented the grit and ingenuity of the industry.


“I’m a big fan of the Greatest Generation and I wanted to do something that was WWII era, like a vet who returned from the war and started a welding business,” Darnell says. “Back then, they kind of took whatever they could find and turned it into a welding truck. I remember when I was a kid, I used to see these older welders come in with trucks like this and they had some of the craziest things built on.”

The 1947 Federal cab Darnell used for the build was an easy decision. Although these trucks are fairly rare, they’re built to last forever as work trucks for the farm, ranch or logging business. Underneath the truck, the frame is comprised of I-beam steel to further illicit the industry Darnell wanted to salute and provides a solid base.

Iron Rod is more than a work of art though, it’s a performance machine and a utility all-in-one. Up front is a 5.9L Cummins out of a ’92 Dodge that provides around 600-hp thanks to a few minor upgrades, including a 12-valve head, an Industrial Injection P-Pump, and compound turbos.

The engine creates a hefty amount of torque, according to Darnell, as well as in the neighborhood of 600 horsepower. Paired with the large FOA shocks and long-travel suspension, Iron Rod is a beast if you felt like taking it out climbing.

“We took it to King of the Hammers, and I drove it probably 25 miles out through the desert,” he says. “The front end is kicked down so far and there’s so much weight on the back that it will just climb straight up a hill.”


While the 5.9L Cummins sits up front to power the truck, mounted in the bed of the truck is a 4BT Cummins engine out of a forklift that is married to the welder.

“We put an adaptor plate from Diesel Conversion Specialists on it and then Merlin Johnson made a flywheel that’ll bolt to it so that we can start it up,” Darnell says. “We also put an Industrial Injection P-pump on it, a cover and compounded the turbos on it.

“The welder probably makes around 130 horsepower, which is funny because it would normally make around 15-22 horsepower. I set it at the right rpm, so I can dial my gauges and actually weld with it, and it’ll burn 7018 MR 1/8-in. all day long. It’s a great welder.”

Another interesting aspect of the build is that the water system actually runs off the front radiator to the rear welder, making it so the welder is always warm. When Darnell pulls up to a job site, everything is ready to go!

Diesel of the Week is sponsored by AMSOIL. If you have an engine you’d like to highlight in this series, please email Engine Builder Editor Greg Jones at [email protected]

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