Factory Options (Generally Easier to Install):
* Jeep's own 232 cu in (3.8L) I6: This was a common engine for the '74 CJ-5. Parts are readily available.
* Jeep's own 304 cu in (5.0L) V8: Also a factory option, though less common than the I6. Parts are still relatively easy to find.
Aftermarket Options (Often Requiring Modifications):
Almost any engine can be shoehorned into a CJ-5 with enough fabrication work. Popular choices among enthusiasts include:
* Various GM small-block V8s (e.g., 305, 350, 4.3L V6): These are relatively common, readily available, and powerful, but will require engine mounts, possibly transmission adapters, and potentially modifications to the firewall and/or body.
* Ford small-block V8s (e.g., 289, 302, 351): Similar to GM small-blocks in terms of availability and power, but also requiring significant modification for installation.
* AMC V8s (e.g., 360): Given AMC's history with Jeep, these can sometimes be relatively straightforward swaps, depending on the specific engine and year.
* Other I6s (e.g., various GM and Ford I6s): These can be an option, often requiring custom mounts and potentially other modifications.
* Modern LS engines (GM's LS series V8s): Popular choices for swaps due to their power and relative efficiency, but they are significantly more involved projects, often necessitating substantial fabrication.
Important Considerations:
* Transmission: The engine choice will dictate what transmission you can use. You'll need to ensure compatibility between the engine and transmission, and potentially use an adapter if necessary.
* Driveshafts: Changing the engine can alter the driveshaft angles and lengths, potentially requiring new driveshafts.
* Cooling System: You might need to upgrade your radiator and cooling system to handle the increased heat output of a more powerful engine.
* Exhaust System: A new exhaust system will almost certainly be needed.
* Wiring: Adapting the wiring harness to accommodate the new engine can be complex.
* Brakes: Upgrading the brakes is often a good idea when installing a more powerful engine.
Before undertaking an engine swap, thoroughly research the specific engine you're considering. Numerous online forums and resources dedicated to Jeep CJ-5 modifications can provide valuable information and guidance. Remember that an engine swap is a significant project requiring mechanical skills and potentially specialized tools.
