Well based on what I can gather I think the pistons are about -13cc. This is sort of an estimate, but I am about to research ways to measure this. I remember someone saying I could use clay and a graduated cylinder to measure. My old man and I have about decided to not pull the motor and just do the top end. The block was rebuilt, god knows why someone put these pistons in it... or maybe back in it.
So the 8.99 compression is with the 64 cc head with these pistons? Well damn... they don't even make this head in with a smaller comb chamber. And the 305 heads that were on this block were supposedly 58cc.
I also tried to measure deck height today but wasn't sure how to deal with the "bevel" around the piston. I guess the deck height would be less than the measurement to the bottom of that bevel.
I guess I'll try to find a way to measure these pistons and report back. Thanks for the help.