There is not an American 351C 2V head that I know of that has enough difference to be worth the change which would leave you with the choice of the American 4V CC heads and the Australian 2V CC heads and after market heads that all will bring up the Compression ratio above 9.5:1. Why not just change out the cam? You would need to change the Cam anyways if you went with the CC heads. Find a good street cam that will work with what you have.