Dissapointing performance

Could try thinner head gaskets. Try for 0.020 compressed. That would put the piston about 0.060" from the head, better than 0.080". When you have the time and before you dive into tearing down the motort, try removing the exhaust and run it with open header. The loss of back pressure from running a 2" system, to an open header you should see a noticeable difference. Do any of your friends have a larger carburetor they could loan you?