This 1966 Ford F-700 Rocks A 5.9L Cummins Diesel And Oshkosh TAK-4 Military Suspension

You don’t see a medium-duty classic like this every day, especially one packing a 12-valve Cummins turbodiesel, Oshkosh TAK-4 independent suspension, and massive 53-inch rubber. Ethan Porter’s diesel 1966 Ford F-700 flatbed is not just unusual, it is a full-blown engineering exercise that rewrites what a vintage work truck can be.

From 361 FE Engine To 12-Valve Cummins

Ethan never planned to build this truck. The original intent was simple. Buy the F-700, strip the flatbed, and use it on a 1976 Ford F-500 project. That plan changed quickly once he realized the F-700 itself had more potential.

Out came the factory 361 cubic inch FE gas engine. In its place went a 12-valve Cummins turbodiesel sourced from a 1996 FedEx box truck. With just 69,000 miles, the engine was a solid foundation. Ethan tore it down to the long block, refreshed wear components, and upgraded it with a slightly larger turbo and an aftermarket three-piece exhaust manifold to address the known weaknesses of the factory unit.

NV4500, NP205, And More

Behind the Cummins sits a proven drivetrain that can handle the Cummins’ torque. The NV4500 five-speed manual came from a retired pulling truck owned by one of Ethan’s friends. It has been upgraded with the fifth-gear fix and a twin-disc clutch to keep it alive under load.

From there, power is routed through a divorced NP205 transfer case that Ethan rebuilt using Northwest Fabworks components. It also features a transfer case-mounted parking brake built with Wilwood parts. New output shafts were installed, and Ethan fabricated adapters that allow the truck to run 1450-series U-joints. The result is a set of equal-length driveshafts that can be swapped end to end if needed.

Oshkosh Defense TAK-4 Units

The original axle plan involved AxleTech 4000 units, but that changed after Ethan came across a pair of Oshkosh Defense TAK-4 assemblies listed on Gov Planet. The price made the decision easy. He placed a bid, won both units, and made the trip to California to pick them up.

Each TAK-4 assembly is a complete bolt-in system that includes coil-spring independent suspension, integrated differentials, pneumatic drum brakes, pneumatic lockers, a central tire inflation system, and 4.63 gears. Oshkosh Defense offers the TAK-4 in Light, Premium Light, Medium, and Heavy variants, and based on the specs, Ethan’s appear to be Medium units. They are rated for an off-road GAWR of up to 23,000 pounds and deliver 16 inches of independent wheel travel along with 15.6 inches of ground clearance on 16R20 tires.

Heavy Frame Modifications

Fitting military-grade suspension under a 1960s Ford chassis is not a bolt-on job. Each TAK-4 cradle measures 39 inches wide, while the factory frame is only 34 inches across. Ethan modified the chassis by adding 2.5 inches per side to properly support each unit.

To run a front-application TAK-4 assembly in the rear, the differential was flipped and custom bars were fabricated to lock the steering spindles in place.

The truck rides on used 16.00R20 Michelin XZL tires mounted to 10-lug, two-piece, internal beadlock, run-flat wheels. Mounting them was a serious undertaking. Ethan notes it took three people 12 hours to mount just four tires, using pry bars, a semi-truck bead breaker, and even a forklift to get the job done.

There’s More

There are many more functional upgrades. Custom tubular crossmembers support the engine, transmission, and transfer case. Fuel is supplied by dual hand-built 35-gallon aluminum tanks. An air compressor and dryer from an 8.3-liter Cummins application manage the truck’s pneumatic systems.

PSC hydraulic steering allows Ethan to easily point the front wheels, while a custom headache rack and vintage-style switch panel handle lighting and locker controls.

The Bottom Line

This build is what happens when diesel power meets military hardware and old-school Ford steel. The result is stone-cold cool.