I have a 1969 chevelle with a 454 in it. When I bought the car the previous owner told me he thought the engine had 11:1 compression.
The engine has 1970 ls-6 square port hi-perf heads on it. I ran a compression check on the engine and the highest cylinder had 240,
the lowest had 225. With these fiqures could anyone tell me if 11:1
sounds like the right compression ratio for this engine? Thanks for
any info. Paul.

I can tell you cranking compression is no indicator of static compression at all.

The intake valve closing point will have the biggest effect past compression.

That sounds pretty high. I would say it is pretty safe to say you are at least in the 11:1 range if you have a cam in the 230o + dur. range with a 110-112o lobe sep.

It's even safer to say that you probably don't have a cam thats big enough for that compression ratio,if this engine is intended to run on pump gas you will likely have a heck of a time keeping it from detonating.

Thanks for the info guys. Maybe this winter i will get the chance to pull the engine apart so i can actually know whats in it, cam, etc. thanks again paul.