* Bolt Pattern: The bolt pattern on the heads themselves is the same. This is the most crucial aspect.
* Intake Manifold: This is where things get tricky. Older heads may have different intake manifold bolt patterns than the 1995 block. You'll need an intake manifold that matches the heads you're using. This means you might need a different intake manifold than the one originally on the 1995 engine.
* Valve Covers: Valve covers from older engines might not fit, depending on the specific head and valve cover.
* Head Gaskets: You will absolutely need head gaskets designed for the specific heads you are installing. Using incorrect head gaskets will lead to leaks and engine damage.
* Exhaust Manifolds/Headers: The exhaust port configuration might differ, requiring new exhaust manifolds or headers.
* Potential for Modifications: You might need to do some machining or modifications to get everything to fit properly. This could involve things like deck surfacing or milling the heads.
* Performance Considerations: Older heads may not be as efficient or perform as well as newer designs. They might have smaller valves or less efficient combustion chambers.
In short, while physically fitting the heads is possible, you'll need to carefully check compatibility with the intake manifold, gaskets, valve covers, and exhaust system. It's highly recommended to consult a detailed parts catalog or a mechanic experienced with small-block Chevy engines before attempting this. Simply assuming they'll work is a recipe for problems.
