heres the background
The last race we had on the motor 383 worlds 220 heads we lost a power steering belt so we just cruise around the whole race, didn't even turn that many RPM's. During our weekly maintiance we notice that the nmber 5 exhuast valve was stuck open a little and would not come up. When we looked further into it we found that the header gasket was blown out a little around the number 3 and 5. So we took the motor out and sent to our engine guys that been helping us with our engines, and very trustworthy engine builder locally. So we are thinking bent valve for sure, but when he took the head off and took the spring off the valve and tap the valve it fell right out, he checked it and it wasn't bent and it moved freely up and down the giudes. The number 5 intake was the same stuck but fell out with a tap of a hammer and then again no binds moves freely. Heads and valves taken to the machine shop heads were mag guides were check and came out just fine. Heads our just fine no problem, no visable marks or any think on the valve stems. Springs are good.
Question has this ever happened to anyone before or anything like this. This is a gas motor 383 with worlds 220 motowns. Valves are straight and true, heads and guides are just fine... Any suggestion, comments, or anything that can help we are stumped.