assuming it is just in that cylinder- bent valve; then you check for compression on the other cylinders (to make sure that it isnt the cam shaft that got stuck and that the piston hitting the valve didnt throw off the rest of the valves) and if you have compression on the other cylinders your in luck. then you gotta take off the head, have it checked for cracks and make sure the piston isnt tottaly f***ed up. and that is just if the valve is bent. broken is worse. im sure im not the only one that has been through it.

66' Chevy C-30 Rat