09-19-2025, 06:56 PM
Ford’s F-SuperDuty Legacy and the 1995 Platform
Before the Super Duty branding became mainstream in 1999, Ford offered the F-SuperDuty as a heavy-duty chassis cab variant of the F-350. The 1995 model featured a robust Dana 80 rear axle, four-wheel disc brakes, and a Gross Vehicle Weight Rating (GVWR) of up to 15,000 lbs. Powered by the 7.3L PowerStroke diesel and paired with a ZF 5-speed manual transmission, it was a popular choice for utility fleets, tow operators, and contractors. Though lighter than modern Super Duty trucks, its payload capacity remained competitive due to its simpler frame and fewer emissions-related components.
Terminology Annotation
The original PowerStroke engine in this build was worn out—firing on seven cylinders and leaking oil rapidly. Rather than rebuild it, the owner opted for a 5.9L Cummins B-series swap. This inline-six diesel, especially in its mechanical 12-valve form, is renowned for torque, simplicity, and longevity. A used unit with 76,000 miles was sourced locally, offering a clean foundation for the conversion.
The Cummins produces peak torque at lower RPMs than the PowerStroke, making gear ratio compatibility a challenge. The Dana 80 axle typically came with 4.63 or 5.13 gears, which are too low for highway use with the Cummins unless overdrive is added. Solutions include:
A contractor in California ran a Cummins-powered Dodge with a Dana 80 and 4.11 gears. After upgrading the engine to 400+ hp and installing a heavy-duty clutch, he peened the 5th gear nut to prevent failure—a common issue in Dodge 5-speeds. He later added a Gear Vendors unit, effectively creating an 8-speed setup that improved fuel economy and drivability under load.
Dump Body Acquisition and Frame Modification
An aluminum J&J dump body was sourced from a 1984 K30 truck. Despite its age, the body was in excellent condition, with only a minor dent in the floor. New retail pricing for this body would exceed $9,000, but it was acquired for just $1,100 including the hoist. To fit the body, the truck’s frame will be shortened, improving maneuverability and matching the dump dimensions.
Aluminum offers several advantages:
To optimize the conversion:
The build relies heavily on used parts and strategic sourcing:
Suggested Design Improvements for Future Builds
This F-SuperDuty transformation blends classic Ford chassis strength with Cummins diesel reliability and modern dump body efficiency. With careful planning and smart sourcing, the project avoids the pitfalls of new truck ownership while delivering a capable, customized workhorse. It’s a testament to mechanical ingenuity and the enduring value of well-built legacy platforms.
Before the Super Duty branding became mainstream in 1999, Ford offered the F-SuperDuty as a heavy-duty chassis cab variant of the F-350. The 1995 model featured a robust Dana 80 rear axle, four-wheel disc brakes, and a Gross Vehicle Weight Rating (GVWR) of up to 15,000 lbs. Powered by the 7.3L PowerStroke diesel and paired with a ZF 5-speed manual transmission, it was a popular choice for utility fleets, tow operators, and contractors. Though lighter than modern Super Duty trucks, its payload capacity remained competitive due to its simpler frame and fewer emissions-related components.
Terminology Annotation
- ZF 5-Speed: A manual transmission built by ZF Friedrichshafen AG, known for durability but limited gear spread.
- Dana 80: A heavy-duty rear axle used in commercial-grade pickups and chassis cabs.
- GVWR: Gross Vehicle Weight Rating, the maximum allowable weight of the vehicle including cargo and passengers.
- CPL Number: Control Parts List number used to identify specific Cummins engine configurations.
The original PowerStroke engine in this build was worn out—firing on seven cylinders and leaking oil rapidly. Rather than rebuild it, the owner opted for a 5.9L Cummins B-series swap. This inline-six diesel, especially in its mechanical 12-valve form, is renowned for torque, simplicity, and longevity. A used unit with 76,000 miles was sourced locally, offering a clean foundation for the conversion.
The Cummins produces peak torque at lower RPMs than the PowerStroke, making gear ratio compatibility a challenge. The Dana 80 axle typically came with 4.63 or 5.13 gears, which are too low for highway use with the Cummins unless overdrive is added. Solutions include:
- Installing a Gear Vendors overdrive unit
- Swapping to a Dodge NV5600 6-speed manual
- Re-gearing the axle (limited options due to housing design)
A contractor in California ran a Cummins-powered Dodge with a Dana 80 and 4.11 gears. After upgrading the engine to 400+ hp and installing a heavy-duty clutch, he peened the 5th gear nut to prevent failure—a common issue in Dodge 5-speeds. He later added a Gear Vendors unit, effectively creating an 8-speed setup that improved fuel economy and drivability under load.
Dump Body Acquisition and Frame Modification
An aluminum J&J dump body was sourced from a 1984 K30 truck. Despite its age, the body was in excellent condition, with only a minor dent in the floor. New retail pricing for this body would exceed $9,000, but it was acquired for just $1,100 including the hoist. To fit the body, the truck’s frame will be shortened, improving maneuverability and matching the dump dimensions.
Aluminum offers several advantages:
- Lower weight increases payload capacity
- Corrosion resistance extends service life
- Easier to modify and repair than steel
To optimize the conversion:
- Use Cummins beige high-temp paint for engine aesthetics
- Install underbody toolboxes to preserve payload space
- Add a transfer tank behind the cab for extended fuel range
- Upgrade brakes if possible; the original four-wheel discs may be insufficient under full load
- Consider a shaft-mounted emergency brake if swapping transmissions
The build relies heavily on used parts and strategic sourcing:
- Cummins engine: ~$2,000 used
- Dump body: $1,100 used
- Transmission adapter or swap: $500–$2,000
- Frame shortening and driveshaft modification: ~$2,000
- Miscellaneous (hoses, wiring, mounts): ~$1,500
Suggested Design Improvements for Future Builds
- Use straight frame rails for easier body mounting
- Opt for 19.5" commercial tires for longer tread life
- Integrate digital gauges to monitor EGT and boost
- Choose transmissions with PTO capability for hydraulic pump integration
This F-SuperDuty transformation blends classic Ford chassis strength with Cummins diesel reliability and modern dump body efficiency. With careful planning and smart sourcing, the project avoids the pitfalls of new truck ownership while delivering a capable, customized workhorse. It’s a testament to mechanical ingenuity and the enduring value of well-built legacy platforms.
