Yeh i used to get the #OOPS#s reshimming the valve clearances. He has mega stiff valve springs which at first pulled the valve seat into the head a bit i think, because we got em spot on when we built it, then about 3 mnths later, had to re do em and there was just about no clearance. Then again after about the same time done em AGAIN!! and there just #OOPS# to do, plus i had a bag full of old shims i had measured with a micrometer and written on them there size, and had to fish through em to get the closet ones i could. Was a real pain in my ass to do lol. But after that time its been sweet.