451 Stroker Build

Ah, well a counterfeit rocker arm could be another explanation. Maybe send a couple of the original rocker arms to T&D and see what they say. I think all "real" T&D rocker arms are engraved with the T&D logo but you would need to double check with them. If you ended up with some cheap knockoffs then all bets are off. They most likely are made from cheap materials and do not have the proper heat treat or finish.