About 9:1 or so.
I ordered everything from Butler Performance.
http://www.jbp-pontiac.com/I had my machine shop cc the heads and gave that number to Butler. Ross racing pistons came out with the correct compression ratio. I think there may have been a slight dome on them.
My cam is colder than a rv spec cam. I may get a hotter cam in the future. I had several phone conversations with Butler performance. My engine build exceeded all my expectations.
I believe it is also possible to have a 455 crank ground down from 3.25 to 3 inches. The trick is in having it radiased correctly. Lots of info on the Wallace Racing site. Ad don't forget this link
http://www.pontiacpower.com/
