Bumping this thread. I also have the 976 heads on my R2. However, I have flat top pistons and this engine has composite gaskets. I do not know who built it.
What am I to suppose my compression ratio is? Before I redo these heads, I am actively searching for the correct 582 heads which I read to be 67 ccs. Sounds like at least a step in the right direction? If my bores & pistons check out OK, I could easily trim a few ccs out of the correct heads in the course of chamber work, this should put me in much better shape than I am now?
What do the experts think?