alright so I'm havin a problem with my rockers, my engine is a later 69 302, i'm running a crower cam with just a lil more perk than a stock, the rest of my valve train is 100% stock, my problem, the rockers on exhaust keep coming loose and then popping off the valve stems after about 5 minutes of running, when this happens the exhaust has no place to go but right out the carb which is annoying and a fire risk.... I replaced the rocker nuts(5/16s) and it still happens, so now I'm gonna replace my rocker arms(which are the original ones that i never had problems with before til i rebuilt the engine), also i noticed that when i go to tighten down my rockers the nut will bottom out on the studs sometimes before the rocker is fully tightened.... anyone have any idea what this problem could be?