The engine has been rebuilt and the heads have been redone, the valves are originalIt has a crane cam 290 dur, at 512 liftI had it running and it started to tick on and offThen it was a sloppy tickI removed the intake manifold and valve cover and noticed exhaust valve was stuck downI pried it back up and started again but it did it againThe question is quot;what could have made this valve bend, could it have been overadvancement on the distribuator? I have crane valve springs that handle up to 600 lift, crane lifters and new rockers so thats not the problem.
Not likelyThat would burn a piston due to detonation, but not stick a valveMost likely either a lifter pumped up on you a piston banged the valveor there is an oiling problem and the valve stuckLook at the sides of the valve stem after you pull it outIf there are marks or discoloration in the guide wear area, think overheating or lack of lubrication to that area of the headIf no damage, think about getting anti-pump up liftersCrane makes em, as do many othersThis helps to avoid those high rpm mishapsYou may even wish to use some putty and do a test build and spin the engine by hand to see the actual clearance, not just rely on the theoretical, between the valves and the pistonsIf the heads have been milled, and the block has been decked, you could be a lot closer than you think.
fart in a container and freeze itthen open it up
