Classic/Antique Car Repair: 1956 Olds oil pump

Question
Just put the engine back together, no re-boring etc and installed an after market oil filter adapter and rebuilt oil pump.Started the engine and blew the seal out of the new twist on filter and adapter. Tried this on a 2nd filter, securing it with a wrench, same thing. Took off filter adapter, put original cannister with new filter  and added an oil pressure gage. It showed some leakage immediately at idle and was at 60 lbs pressure after a few seconds. I later found the filer bolt was not torqued to 40 psi. will torque to proper spec and retry. I think the relief valve spring in the pump is suspect. I have the specs on the spring but no way to test it. Any suggestions appreciated  ps the pump was bought several years ago and I have no way of knowing if a replacement pump might have the same problem.

Answer
You are on the right track but my first suspect would be the pressure relief valve itself. I would check to make sure that it was not stuck in the bore. Like rusted from sitting on a shelf. I live in southwest Florida and we have a major problem with rust from sitting on cast iron parts. In any case the max oil pressure that you should see in your engine should be in the 40 PSI range. And I would suspect the valve plunger rather than the spring.