[Slammed84]

Did you make sure the pushrods were the correct length? If you reused the old ones the tips of the rockers might be sliding off the valvestem?

Im trying to think outside the box here, I know its not likely but stranger things have happened.

I just got done tightening one rocker arm on my buddies vortec crate engine we installed a couple years ago. It was number 8 exhaust. We didnt touch the rockers during installation and everything looked perfect under the cover. Just that one rocker was loose, the nut just decided to back off that day. ???