As A Cummins-Powered ’51 Chevrolet
You see them all the time, especially during planting and harvest season. The service trucks that show up in the field to keep equipment running are the backbone of any farming operation. When he didn’t like the prices he was seeing while shopping for the family farm’s new service truck, Chris Ohl decided to take matters into his own hands with an old Chevy truck. He would build it himself—and it would be one of a kind. After all, his great grandpa’s ’51 old school Chevrolet 3800, a 30,000-mile 1-ton grain truck that’d been parked for a number of years, was practically begging to be transformed into a service rig.
Combining his wrenching, welding and auto body skills with the knowledge he’d amassed in other encounters with the 12-valve Cummins, Chris set out on what would become a year-long journey to bring the old Chevy back to life. A quick trip to Ohio yielded the second-gen Dodge chassis and axles he would set the ’51 cab on top of, along with the P-pumped 5.9L that would power the truck. Aside from having to address a rusted driver side cab corner and fender, the body was straight as an arrow and in what Chris believes was good-to-excellent condition, given its age. All of the new sheet metal and welds were left raw, and with no clear coat to speak of, Chris keeps the Patina preserved and protected with Gibbs penetrating oil.
A Tight Fit
Other than things being a bit tight under the hood, no notching of the firewall was necessary to accommodate the Cummins. In fact, the engine would be set back 4-inches on the frame after setting the cab on a pair of fresh cab mounts, which also called for repositioning the motor mounts. However, even with engine moved close to the firewall, little room remained for an adequately sized radiator. Instead of sacrificing cooling capacity, Chris purchased the largest off-the-shelf radiator Ron Davis builds and mounted it in the bed. Then to ensure the engine remained intercooled, he sourced a water-to-air unit from Precision Turbo, which sits suspended above the valve cover.
As for the engine itself, Chris dropped it off at Scheid Diesel’s Effingham, Illinois location for a full refresh from the bottom up. The factory rods were retained but treated to ARP rod bolts and new, stock compression Mahle pistons. Scheid’s 12-valve street cam also made the build list, along with fire-ring grooves being added to the block for ultimate peace of mind. A remanufactured cylinder head fitted with stiffer valve springs is anchored to the crankcase via ARP 2000 head studs. A billet-aluminum, one-piece Scheid valve cover and intake plate top things off.
Benched P-pump And An S300
Turning Scheid’s injection shop loose on the P-pump meant that it could easily support a 500-rwhp effort, should Chris want to take things that far. The benched 12mm P7100 was graced with 4,000-rpm governor springs, larger delivery valves, a rack cap, and lives at 18-degrees of timing. It sends fuel to a set of 5×13 injectors, also built by Scheid. A 58mm BorgWarner S300G turbo matches the engine’s fueling and produces 35-psi of boost before the wastegate opens.
Like a lot of 12-valve swaps, Chris sided with the rugged NV4500 manual transmission to back up the 5.9L, but in this particular case there’s a twist. A Gear Vendors overdrive allows him to split gears, which with nine forward gear options makes the truck much more efficient when tasked with moving heavy loads. A single disc towing clutch from South Bend, along with a solid mass flywheel, dwells inside a Quick Time bellhousing and transfers power to the rear Dana 80 (and also the front Dana 60 when the NP241 is locked in four-wheel drive).
Always In Service
Already having racked up several thousand miles on the finished product, Chris has held true to his original plans for the truck: to drive it and put it to work. During the farm’s busy season (primarily spring and fall), you can find his old Chevrolet out in the field, loaded up with a massive air compressor, welder generator, and 200-gallon fuel cell. Moving trailers and other equipment around is all in a day’s work, too. Chris tells us the truck pulls the farm’s 12,000-pound, bumper-tow seed tender with ease and, thanks to the Kelderman air spring system, rides like a newer service truck while doing it. Whether it’s off the beaten path and parked in a field or cruising down the highway, this reborn family heirloom will be turning heads for a long time to come.