I was hoping for something better from ACDelco. The first aspect is that the bolt is not exactly suited for the specified application and secondly, to facilitate adjustment of the cam portion of the bolt, I believe the plastic part is shifted slightly which can dramatically alter your reading if it slips misaligned on the place. It may be perfect for the right application and I'm still a big fan of ACDelco/GM parts, but that doesn't quite fit even though it's made in the USA.