Factory Options (Easiest Swaps):
* 2.5L 4-cylinder (AMC): This was a common engine. Finding a replacement is relatively easy.
* 4.0L 6-cylinder (AMC): Another common and popular option. This is likely the most common swap, even if you didn't originally have one.
* 2.8L V6 (GM): Less common, but still relatively straightforward to swap if you can find one.
Other Engines (More Challenging Swaps):
Many other engines *can* be made to fit, but it will require significantly more work, including custom mounts, potentially modifying the firewall, driveshafts, and possibly the transmission. This level of work usually requires fabrication skills and welding. Some popular choices for more involved swaps include:
* Various GM V8s (e.g., 350 Small Block, LS series): Very popular swaps, but require considerable fabrication.
* Chrysler V8s: Similar to GM V8s in terms of difficulty.
* Ford V8s: Also popular but require significant modification.
Important Considerations:
* Transmission: The transmission must be compatible with the engine you choose. You might need a new transmission or an adapter to mate the engine and transmission.
* Computer/Wiring: Modern engines will require significant wiring modifications, possibly including a stand-alone engine management system. Even older engines might require some rewiring.
* Driveshafts: You'll likely need custom driveshafts depending on the engine and transmission combination.
* Exhaust System: A custom exhaust system will almost certainly be needed.
* Cooling System: The cooling system may need upgrades to handle a more powerful engine.
In summary: While the 2.5L and 4.0L AMC engines are the simplest swaps, plenty of other engines can be fitted, but it will become a much more involved project. Before embarking on an engine swap, carefully research the specific engine you're considering and the level of fabrication required. Online forums dedicated to Jeep Comanches are invaluable resources for this kind of information.
