Valve stem seal relacement

[Anonymous]

Hi there this is my first post. I have a 66 mustang coupe, with the original 200 engine, that has 70,000 miles on it. The engine has never been apart. I'm wondering when using an air compressor, via the spark plug hole. How much psi should be used to keep the valves from dropping? I don't want to blow the head gasket. Can I get the valve stem seals from my local parts house, Napa, Checker. Autozone, CarQuest? Thanks for any input.

 

[BIGREDRASA]

Not to worry. Compression without ignition can go up to 170 PSI, and way past that when the mixture ignites.
You should be able to use 100-120 PSI with no probs. Just don't crank it up to 3,000 PSI.