you'll need at least 60# compression to burn fuel,anything more the better, 10 # oil pressure will be enough anything more is better, if she's got these she's still got life, probably alot if you keep RPM under 2500, sticky valves poor ingition are your worst enemies,Marvel Mystery Oil in the oil for the valve guides and convert dist. over to the solid state, kit aviable, easy to install, waa-la purrs like a kitten, starting problems cured.Motor designed for leaded fuel so add stablazier at least every other tank, she may out last you!