does sound head gasket or valve seat. how far out was your valve set on offending pots? get it running with radiator cap off and you should find plenty of bubbles in the coolant if its head gasket. i wouldnt bother with oil change straight up; get this motor warm then try another comp test. bit of engine heat and your mm oil may help if the issue is a couple stuck rings from sitting around. drop the oil when you are resolved to either pull the head or not.