A 12-Valve Cummins ’49 Power Wagon on 39’s
What happens when you treat the baddest 1-ton 4×4 Classic Dodge truck of all time to a 12-valve Cummins swap, Dana 60 front axle and 14-bolt rear axle, and completely modernize the cab? You get this one-of-a-kind ’49 Dodge Power Wagon owned by Carl Van Rooy. Turning to friend, fabricator, and off-road specialist John Conrad of J.B.’s 4×4, the project took root, got underway, and was ready for delivery 13 months later. In Conrad’s care, he and his crew made the war-born Power Wagon much more than the tractor it essentially was when it left Chrysler’s Warren, Michigan assembly line some 70 years ago.
Restoration & Repower
The cab-off restoration, powertrain swap, and drivetrain upgrades all took place at Conrad’s Kingman, Indiana facility, with most outsourced work on select components and pieces primarily being performed at local businesses. The Power Wagon’s original frame was powdercoated and modified to accommodate repositioned motor, transmission, and fuel tank mounts, along with relocated leaf spring brackets. PPG provided the base paint that’s about as close to the old Ponchartrain Green as they come.
Making The Cummins Fit
Well known for their ability to convert classic off-road rigs to 6BT or even 4BT power, the guys at J.B.’s 4×4 were definitely up to the task of making a 5.9L fit in the Power Wagon’s narrow engine bay. A set of modified second-gen motor mounts solved the positioning of the Cummins easy enough, but its front-to-back length was the real worry. Stacking all the heat exchangers behind the grille and not having to push the Cummins through the firewall in order to accommodate everything was where Conrad and his crew were most resourceful. The radiator issue was solved by fabricating an aluminum unit in-house, along with an expansion tank which was mounted above the number one cylinder (and between the air intake and cold-side plumbing). Bell Intercoolers supplied the compact air-to-air intercooler that keeps the 12-valve’s EGT in check. An air cleaner from Unique Metal Products also makes for good use of space near the firewall.
Starting with a 470,000-mile running donor, the ’96 model year 12-valve Cummins was torn down for a full-on refresh. The block checked out OK but a crack in the head was all the convincing needed to source a brand-new one, complete with 60-lb valve springs, from Phil’s Automotive Machine Shop in Danville, Illinois. From there, six new stock replacement pistons from Mahle went in, along with fresh bearings, seals, and gaskets from top to bottom. The engine’s fuel system was also renewed thanks to six remanufactured injectors and the P7100 being treated to a considerable advancement in timing, a custom grind fuel plate, and higher rpm governor springs. A 63mm S300 SX-E turbo from BorgWarner handles boost production and spins to life quickly.
Built 47RE & NP205
Building a 47RE that would never flinch under the load of 700 lb-ft of torque and the strain of turning 39-inch mud terrains, the second-gen-derived four-speed was reinforced throughout, equipped with a RevMax Stage 5 triple-disc converter and high-pressure valve body, and topped off with a Mag-Hytec deep pan. An Anteater Classic STC transmission controller from Firepunk Diesel allowed the guys at J.B.’s 4×4 to dial in the automatic’s shift points, as well as its lockup and Overdrive strategies. Thanks to a first-gen donor, an NP205 transfer case is married to the 47RE, along with an E-brake assembly from Moonshine Mafia Motorsports. Custom length driveshafts from Patterson Driveshaft send power to the front and rear axles.
Dodge Dana 60, GM 14-Bolt
Axle selection boiled down to the tried and true Dana 60 up front and a GM 14-bolt in the rear. Both make use of a 3.73 ring and pinion, but the 14-bolt was treated to a Detroit Truetrac differential, with its axle tubes serving as mounting points for the traction bars that link the axle to the frame. The Dana 60 sits below first-gen intended leaf springs and features a host of steering upgrades. The steering box was relocated and fitted with a high steer arm, a custom pitman arm and PSC cylinder-assist components were added, and a heavy-duty tie rod assembly also made the cut.
The Ultimate Power Wagon
The original Power Wagon was known for its simplicity, durability, hauling capability, and off-road readiness, but Carl’s takes things several steps further. The rebuilt P-pumped 12-valve Cummins swap and reinforced 47RE bring million-mile durability to the table. The Dana 60, Truetrac-equipped 14-bolt, 39-inch BFGoodrich Mud Terrains, and 12,000-pound Warn winch provide endless off-road capability. And finally, the show-quality frame, body, and bed restoration—along with the completely refinished and updated interior—make it one of the finest classic repowers we’ve ever come across.