The heads that we have are 113cc open chamber. The piston hits about an inch from the spark plug hole. The head lacks about .150 " from sitting down on the block, with the piston at tdc.
I called Keith Black piston company and they said that I needed 119cc open chamber heads. This will give me 10.6:1 cr. I have checked the casting #'s on the internet and I could not find the part # for a 119cc.