AMC used the 304 cubic inch, V-8 engine in earlier CJ-series 4WD vehicles. Later models used the 2.5- and 4.0L engines. Jeep engines, while reliable in standard form, aren't all that powerful in newer models. Small block Chevy engines (SBC's), however, can be designed to generate significantly more power. Even in standard-performance form, an SBC generates much more torque. In addition to the extra power, swapping an SBC adds a lot of "wow-factor" and is sure to turn heads. A conversion is not without complications, however, and adapter kits are required to make the swap.
Locate and purchase an engine and transmission. The engine can be located at a salvage yard, often with a warranty. Be certain to buy an engine with all the accessories, brackets and drives. An alternative is to buy a new crate engine with all the accessories attached. The GM TH 350 automatic is a good choice, but it's also possible to continue to use the factory Jeep manual transmission.
Purchase the conversion kit. These kits usually include new engine mounts and fastening hardware. In addition to the engine mounts, planning is required for the transmission and 4WD transfer case. If the factory Jeep manual transmission is being used, a bell housing adapter is required. If a GM Automatic transmission is being used, then an adapter for the Jeep transfer case for the GM Transmission is needed, as well as a new transmission cross member.
Plan for other considerations, as well. Two larger items to plan for in the conversion are the exhaust and cooling systems. Factory GM exhaust manifolds may be used, but custom exhaust tubes will need to be fitted. An alternative for increased performance are exhaust headers. These are readily available from conversion kit manufacturers. The factory cooling system (unless it is in an early model formerly equipped with a V-8) will not likely be sufficient for the larger engine. An aftermarket conversion radiator should be installed.
Remove the engine with an engine hoist. Install the conversion engine mounts and test-install the replacement SBC engine. Follow the conversion kit manufacturer's instructions.There will be a fair amount of test fitting, some slight modifications here and there for clearance. Plan for several trips to auto parts stores.
