Well, I FINALLY figured out what was wrong with the GTO. After I took it apart, I saw my side of the engine held together. Nothing loosened up at all. ......and that was the problem. Whatever jack hole came up with this combination should have his finger nails removed with rusty pliers and forbidden to touch another tool as long as he lives.
The problem was the combination. He had oversized, triple valve springs on a relatively stock, flat tappet cam. ...That's over
SIX HUNDRED psi open! These are the springs you need to run a full roller cam with gross lift in excess of .600". The adjustable stock Chevy nuts couldn't hold that kinda' force and slipped up the studs. The only reason the studs didn't fly out of the engine was because they were ARP studs. Since I got the valves to hold adjustment, all that force was displaced to the next thing in line. .....the cam. It snapped the cam off clean in between two bearings.
The engine is getting pulled tomorrow and sent to the machine shop. The combination didn't work at all anyway. A stock engine would've outrun this turd.
Bigger is not always better, and more expensive doesn't mean faster. Do your research and come up with a combination of parts that works well together. Or you could just throw money into a burn barrel. It'll have the same effect in the long run.