Pknowles, Yeah, you would. This motor was rebuilt by S&S and the noise started after the rebuild. Since it is under warrantee, I have been going through S&S. Lifters have been changed out 3 times... rules that out. Markey-Marc, thanks for the input. With the motor just rebuilt by S&S, I would have thought they would check the rocker shaft clearances. I am also considering that since the noise only appears after full operating temp has been reached, that maybe the spring collars might be slightly hitting the inside of the rocker box at operating temp. Sound plausible to you?