* Motor Mounts: You'll need motor mounts specifically designed for a small block Chevy in a 1998 Jimmy chassis. The existing mounts are for the original engine.
* Transmission: The transmission needs to be compatible with the small block. You'll likely need a new transmission, driveshaft, and potentially modifications to the transmission crossmember.
* Exhaust System: A completely new exhaust system will be required.
* Wiring Harness: The wiring harness for the original engine won't work. You'll need a new harness or significant rewiring.
* Computer/ECU: The engine management system will need to be compatible with the small block. This may involve using a standalone engine management system or adapting the factory system (a complex undertaking).
* Radiator and Cooling System: You may need a different radiator and possibly other cooling system components to handle the small block's cooling requirements.
* Accessories: Consider the alternator, power steering pump, and other accessories – their compatibility and mounting points will need to be addressed.
* Firewall Clearance: In some cases, firewall modifications might be needed, depending on the specific small block and its accessories.
In short, while it's *possible*, it's a significant project that requires mechanical expertise and likely significant fabrication and customization. It's not a weekend job. You'll need a good understanding of automotive mechanics and likely access to specialized tools and equipment.
