273 Performance build possibilities.

Higher compression on the SBM is detrimental to head gaskets. Ask me how I know, I was running 12.0 to 1 compression pistons in a street car with a 273 in the early 70's. I ended up contacting Ed Hamburger and he spec'd out putting SS o-rings in my block and running his copper sandwich gaskets. This indeed stopped me from blowing out head gaskets.