I am a new rider. I just purchase a project 97 wide glide and need to either install new pistons and heads. My compression is 120 psi. I´ve been reading up and it should be about 140 - 150. Also there is a serious knock in cylinder 1 intake rod. Basically the question I have is, the motor is 1330.c.c. 81.75 c.i. what size heads I can install to upgrade the performance Without modifying everything on the bike.