Stockers are usually just a press fit into the head, not screwed in like high performance ones. So if you get enough pressure on them, they will lose their grip and start coming out. I had a 389 Pontiac with a 421 cam in it. I carried a big hammer with me because these would pull up occasionally, and I would just hammer them back down.

The more they come out the looser the fit becomes. Someone on here will be able to tell us if there are oversized ones or whatever to fix the problem.


Don