1980-1997 Ford OBS Cummins Swap
The 1980 to 1997 Ford F-Series is one of the most popular platforms for a Cummins swap. The frame is straight, the engine bay is huge, and the trucks are old enough that you can build them however you want without fighting modern emissions equipment.
Why Swap a Cummins into an OBS Ford?
- The factory 7.3L IDI is reliable but underpowered (170 hp from the factory).
- The 7.3L Power Stroke is better but the IDI is becoming hard to find parts for.
- The 460 gas engine drinks fuel like it's free.
- A 12V or 24V Cummins drops in cleanly and triples the durability of the drivetrain.
Recommended Engine Choices
For OBS trucks, the 12V (1994 to 1998) is the most common pick. No ECM to wire, no sensors to source, and the truck stays simple. The 24V works too but adds complexity. CR Cummins swaps into OBS trucks are possible but the wiring is significantly more involved.
Transmission Options
- ZF5 manual — factory in 1987-1997 7.3L trucks. We make adapters for 12V, 24V, and CR Cummins.
- ZF6 manual — uncommon in OBS but a strong upgrade.
- E4OD automatic — factory 4-speed auto. Decent for low power; not recommended for built engines.
- 4R100 automatic — the later E4OD with electronic controls. Stronger than the E4OD.
What You'll Need
- An adapter plate between the engine and transmission.
- A flywheel (manual) or flexplate (automatic) with the Cummins-to-Ford bolt pattern.
- Motor mounts that locate the Cummins correctly in the frame.
- An AC/alternator bracket if you want to keep both running.
- A throttle linkage solution.
- Wiring and fuel-system plumbing.
Shop OBS Cummins Parts
We carry every machined component you need for this swap. Click below to see kits and individual parts.
→ Shop 1980-1997 Ford Cummins Parts
Have Questions?
Call or text us at (612) 479-0926 before you order. We will help you figure out exactly what your build needs.
Related Swap Guides
- 1999-2002 Ford 7.3 Cummins Swap Guide
- 2003-2007 Ford 6.0 Cummins Swap Guide
- 2008-2010 Ford 6.4 Cummins Swap Guide
- Compare Conversion Kits — 12V vs 24V vs CR Cummins side-by-side
- Cummins Swap Glossary — plain-English term definitions
- FAQs — the questions we get every week
