Have valve stem damage to the ends of the stem from the roller rocker, the exhaust only are extremely worn down. Had a valve train job done to the engine and a few months later the car wouldn't run properly, when removing the engine the problem was found. i have a new 455 build going on right now to replace the 455 and now with this issue cropping up I don't want it to happen again to the new build. Any ideas? Stock cam, new roller rockers, springs, caps, pushrods, etc.

Need some guidance in this, never seen it before.

thanks

 

Pictures?