[WILMASBOYL78]

Originally Posted by big gear head

I'm running open chamber pistons. I measured the combustion chamber volume, head gasket volume and piston dome with a piston deck height of about -.005 and did the math. It came out to 10.99:1, which is pretty much 11:1. The open chamber shape and aluminum material may help. I also probably have more valve overlap with my cam than what a stock L78 cam has, which would lower the cranking compression.

Sounds like you have a nice setup on that motor...the cam duration will 'bleed off' some cylinder pressure and help the cause. What kind of HP does it produce??? Enjoy all this stuff now...with the way things are going, our hotrods will only exist in museums or magazines