* Engine Code: The most crucial factor is the *specific engine code*. Both cars used several different engines (e.g., different variations of the 2.2L and 2.4L). You MUST verify that the engine codes match or are directly compatible. Look for the engine code stamped on the engine block itself. A simple difference in the code can mean incompatible components (like different intake manifolds or sensors).
* Transmission Compatibility: Ensure the transmission from the 1998 car is compatible with the 1995 car's transmission. Automatic and manual transmissions are not interchangeable. Even if it's the same type (automatic or manual), there might be subtle differences preventing a direct swap.
* Wiring Harness and Computer: The wiring harnesses and engine control modules (ECMs) are likely different. You might need to swap the harness and ECM from the 1998 Cavalier or adapt the existing harness, which can be a significant undertaking.
* Mounts and Accessories: While the engine block itself might fit, the mounting points and placement of accessories (like alternator, power steering pump, etc.) could vary slightly. You may need to adjust or swap some components.
In short: Don't assume compatibility. Before attempting the swap, meticulously compare the engine codes, transmission codes, and verify all the other potential compatibility issues. A mechanic familiar with these vehicles would be highly recommended. A simple mistake could lead to a non-functional engine, or worse, damage to other car components.
