having a little issue...

I would think if seat failed it would have made a huge commotion banging around in the cylinder?

well that kinda what i was thinking but then again the valve spring would just hold everything tight...

Yes. and it would also seem if the valve is hung open that far, well.....something came up and hit it.

even with everything i milled off i still had like over .1" of clearance...

but will see tomorrow when i pulled the head...

also when it happened i thought that i lost a spark plug wire, kinda just started missing, so will see...