just rebuilt topend, and put on cool head, had cylinders ported, took it to oklahoma ran very very strong for the first day then started spitting up out of the overflow. Put in new impeller and gear even though everything looked good didn't help. Put on KNOWN good radiator cap NO help, Put in new engine ice NO help, Plugs look good. When i went to drain oil to take off side cover to replace water pump oil pressure seemed so high could hardly get drain plug out. Start it up and shut it off there is a ton of oil pressure, can tell just by taking out dip stick. Does this maybe have any thing to do with the overheating problem or should i start at the head gasket? Thanks for any help...