....to see if there are any factory steel heads, with 100 cc combustion chambers, that will work with my motor. My local machine shop has a computer program that computed a compression ratio of 9.04:1 using 100 cc heads on my motor.
I reallly don't want to go any higher than that. I'd have to use premium fuel.

Heads have to be able to accept anti knock sensors that are screwed into heads.