Things to consider when choosing an engine swap:
* Engine bay space: The Caprice has a relatively large engine bay, but it's not limitless. Larger engines might require modifications to fit, possibly including firewall modifications, custom mounts, and possibly even modifications to the hood or other body components.
* Transmission compatibility: The transmission needs to be compatible with the engine you choose. You might need to swap the transmission as well, which adds complexity and cost.
* Wiring harness: You'll likely need to adapt or replace the wiring harness to accommodate the new engine's computer and sensors.
* Exhaust system: The exhaust system will probably need to be custom-fabricated or significantly modified.
* Driveshaft: The driveshaft length might need adjustments depending on the engine and transmission combination.
* Cooling system: The cooling system might need upgrading to handle a larger or more powerful engine.
* Legal and safety considerations: Check your local regulations regarding engine swaps before proceeding. Improperly done swaps can lead to safety issues and failure to pass inspections.
Engine options (considering practicality and difficulty):
* Larger Small-Block Chevy (SBC): Engines like a 350 cubic inch (5.7L) or even a 383 stroker are relatively common swaps and are likely to fit without major surgery. These are popular choices due to their readily available parts and aftermarket support.
* Big-Block Chevy (BBC): A Big Block Chevy (454, 427 etc.) would require more significant modifications and might necessitate extensive fabrication to fit in the engine bay. This is a much more involved project.
* LS-series engines (from later GM vehicles): These are relatively popular swap choices because of their performance and efficiency, but they require significant modifications to the engine bay and considerable fabrication work for the wiring harness, engine mounts etc.
In short: You could potentially put a fairly wide range of engines into your Caprice, but some will be much easier and cheaper than others. A larger small block V8 is a good starting point for a relatively straightforward swap. Bigger engines and those from different manufacturers will significantly increase the project's difficulty and cost.
Recommendation: Before you start, thoroughly research engine swaps specific to the 1991 Chevy Caprice. There are many online forums and communities dedicated to this, where you can find detailed guides, parts lists, and advice from experienced enthusiasts. Talking to a professional mechanic who has experience with engine swaps is also highly recommended.
