Good morning V8Buick, I've been researching ways to increase compression without breaking the bank. I've also decided to go with Comps 268H which supports up to 9:1 CR. The engine is still stock except that I've started the intake swap and realized the factory carb has thermal choke. I'm waiting for choke to arrive. Anyway, back to my point. I've searched high and low for a head shim for this engine and cannot seem to find one. Any ideas where to find the correct shim? Thoughts on milling? I'm current running premium / high octane because the engine would knock with 87. Planning to order cam tomorrow to replace lifters and timing chain too while I have the intake off. Thanks for any response.