high oil pressure 85+psi

I recently just over hauled a 20R and we have run into a series of problems the oil pressure is being the biggest one at the moment. we have blown out three oil filter gaskets. put a gauge on there to see what it says and its at 85+ psi just off of the starter:shakehead we have removed the plunger for oil pressure relief valve and moves freely the gasket surface where the filter goes was fine the oil wt is 10-30 not sure what else to say but I am at wits end right now. Ideas thoughts divine revelations etc.