My old 440 I ran right at 10.0 comp with 906 heads. I did use the KB quench pad pistons and got quench at right around .045. With the MP .557 cam it ran fine on 92 pump and is still running on 92 pump today in another car. But my 906 heads had been milled alot before I got them and I had to use Cometic head gaskets that were .074 thick to get the 10.0 comp with the KB quench pad pistons. You can get all different size thickness on the head gaskets from Cometic. They go from about .018 up to .128 I believe and they can also make other sizes I believe but of course they cost more. Ron