I don't know how one would classify my motor. I did all the port work myself. If I change my base gaskets then I have to change domes again. I had .015 thick paper base gaskets in it just prior. It changed my compression by 10 psi. So I was at 170 psi. I went back to the .030 oem's and it dropped to 160psi. Replaced the 20cc's with 21's and now I'm at 150psi. Since the bike is running good. I'm leaving it till the next blow up.