Black Beauty

Seth Johnson’s body-swapped C/10 Cummins

July 2021 Feature Chris Tobin

This article originally appeared in the June 2021 issue.

No doubt you have heard the expression, “When life gives you lemons, make lemonade,” but in many cases it is much easier said than done. This was the case for Seth Johnson, a 26-year-old Indiana state highway worker from Brazil, Ind., when he wrecked his beloved 1999 Dodge RAM 2500 not long after graduating from high school. The truck was a total loss and written off by the insurance company, leaving him with no ride. Rather than wallowing in his loss, he purchased the remains of the truck back from the insurance company and went to work salvaging the chassis and drivetrain.

But having a functional chassis and drivetrain wasn’t enough to drive to work or take his wife Brooklyn out on a date, so he needed a new body to round things up. Johnson and his father had seen a classic Chevrolet C/10 sitting in a nearby field and decided it would be a great match for the Dodge chassis and Cummins engine. The owner of the truck wanted it to have a new life and Johnson was the one to make it happen.

Coming Together

After removing the damaged bed and cab from the truck and verifying that the chassis was indeed still straight, Johnson set about getting the running gear in order and dressed up to make it look and perform well as he melded the newer Dodge chassis to the older Chevy body. Rather than try to work with the Dodge cab and bed mounts and adapt them to work with the 50-year-old body, he completely removed the existing mounts and fabricated all new mounts to secure the cab and bed to the chassis, giving him a functional truck once again. But he wanted more than just functional; he wanted his truck to be special and that required work—lots and lots of work!

While the suspension retains the factory Dodge configuration, Johnson upgraded the ball joints with Dynatrac rebuildable units to firm up the front end and improve longevity. The original 3.55-geared Dana 60 and Dana 80 axles were dressed up with a fresh coat of chassis black paint to match the reworked frame. The chassis rolls on a set of 33X12.50R20LT Atturo Trail Blade M/T tires that are wrapped around 20x12-inch Fuel Maverick 8-spoke wheels with chrome centers to give the classic truck a modern look without going overboard.


The next area Johnson turned his attention to was beefing up and improving the performance on his 24-valve Cummins engine. His goal was to build a street-legal engine that would be reliable while also having enough power to be fun whenever he mashed the loud pedal. Leaving the robust internals in the Cummins stock since they are known to handle upwards of 1,000 horsepower without issues, he focused on improving fuel flow and high RPM control.

With the original valve cover removed, Johnson replaced the factory valve springs with a set of performance valve springs from Hamilton Cams, then installed a color-matched Cummins Industrial valve cover. He also replaced the stock fuel injectors with a 250hp set from Scheid Diesel that are fed plenty of #2 through a set of .093 stainless steel fuel lines and a P7100 P-pump conversion rather than the original VE-pump. To improve performance further he upgraded the pump with a set of Full-Cut delivery valves and 5k governor springs to deliver large amounts of fuel even while spinning at high RPM. An SFI-rated billet ATS Diesel flexplate is used to link the engine to the billet Recon torque converter, sending the estimated 600 horsepower to the Dodge 47RE automatic transmission.

Townsend Transmission

Of course, with the upgraded power Johnson worked into the Cummins, the original trans would need some help to survive, but rather than tackle the automatic trans upgrades himself like he did with the engine upgrades, he turned to the team at Townsend Transmission in Martinsville, Ind., to handle the performance rebuild. They upgraded the internals with billet input, output, and intermediate shafts as well as high performance clutches while performing other upgrades to make sure the transmission would handle the Cummins power without an issue. They also built a full manual valve body for the transmission so Johnson can be in total control of gear selection through a B&M Stealth ratchet shifter from Holley that is perched atop a custom-fabricated steel mount forward of the bench seat on the transmission tunnel.

Exterior Touches

To rejuvenate the rusty ’70 C/10 bodywork Johnson turned to Josh Basham in Terre Haute, Ind. Knowing that Johnson wanted to go with a dark color on the truck made Basham extremely focused on delivering a flawless surface to lay down the Tuxedo Black metallic finish paint. In addition to rust repairs, he also shaved the original antennae and the vents in the cowl below the windshield as well as the debossed CHEVROLET letters in the tailgate. He also prepped the aftermarket 2-inch steel cowl induction-style hood, making sure it was in perfect shape for the bold color choice. After laying down several coats of Tuxedo Black metallic base he covered it in ample layers of high gloss clear, then cut and buffed it to perfection, leaving behind a glass-smooth finish that is exceedingly deep and shows no signs of surface or body imperfections normally associated with dark colors on classic sheet metal.

Light It Up

To dress up and complement the new paint Johnson refreshed the original Chevrolet grille and headlight bezels then added a set of Auxbeam LED headlights to cut through the darkness. Below the grille he replaced the well-seasoned factory bumper with a new replacement chrome bumper from LMC Truck and installed a set of flush-mount Auxbeam LED pod lights as well as a black and chrome Cummins logo license plate to give onlookers a clue as to what’s under the steel hood.

Moving to the sides of the truck he installed new replacement marker lights from LMC Truck. Rounding the corner to the rear of the truck you’ll find another bright chrome LMC Truck bumper also with flush-mount Auxbeam LED pod lights installed. Each rear corner is dressed up with a new set of taillights from LMC while the bed is capped by a tonneau cover from Truxedo, a Truck Hero brand that conceals the bed-mounted fuel cell.


To complete the final touches and make his C/10 show-worthy Johnson addressed the interior. Painting the dash and interior sheet metal in matching Tuxedo Black paint was handled by Basham while he painted the truck, meaning that Johnson didn’t have a ton to do to finish up the interior. Somehow the original black leather bench seat was still in good shape, so he cleaned it up and reinstalled it in the cab in the factory location. New replacement carpet came from LMC Truck and installed easily to give the interior a finished look when coupled with the black headliner above and door panel inserts to the sides. He retained the original gauge cluster and at the time of our photo shoot did not have a head unit installed, but he has since installed a factory replica radio with modern Bluetooth features to blast the tunes while the Cummins sings along as he rolls down the road.

Looking at the finished truck it is easy to see that Johnson’s hard work and determination paid off. He entered the truck in the famous Scheid Diesel Extravaganza show-n-shine and won the Best Custom award in 2018. While working on the truck project he and his father drew close to the former owner of the C/10. After finishing the build, they took the truck over and showed him how it turned out. He was overwhelmed and with tears in his eyes said that he couldn’t believe it was the same truck and that he was happy that the truck was in good hands and brought back to life from the old truck that sat in the weeds. So next time life gives you lemons, think about this amazing C/10 showing that even a totaled truck and a rusty classic can be turned into a stunning showstopper!





ATS Diesel Performance



Atturo Tires









Fuel Wheels


Hamilton Cams






LMC Truck






Scheid Diesel



Townsend Transmission



Truck Hero




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