The oil pump relief valve is located in the oil pump cover. Did you replace the oil pump cover with the new pump? I don't know but you can check to see if the valve can be cleaned or replaced with the new cover I listed below. Just a thought.
I found and interesting service bulletin on oil pressure. I listed it below. I hope this can fix your problem. It explains too much pressure because of a sticking relief valve. You may have the opposite problem.
In the long run you can spend a lot of time on this problem and a lot of money, if you like doing all of this work then it is an interesting project to find the problem. In the case of sanity, the oil ran dry and the engine locked up. Not a good sign. You could change the cam bearings with out removing the engine and after replacing the bearings you may have the same problem.
Installing a re manufactured engine in a near perfect car (as you explained) can have you enjoy the car for many more years.
Update us when you can.
87-02 August 5, 1987
4 Cyl. Except
Oil filter leaks - factory rebuilt engine
A leaking oil filter when a factory rebuilt engine is first started, may be due to excessive oil pressure caused by a sticking oil pump relief valve.
If this occurs:
Install improved oil pump cover with larger relief piston (19 mm), Part Number 055 115 151E.
Improved oil pump cover installed as of Oct. 1984, Engine Number: VC64754.
The new pump was complete and sealed with only the key shaft protruding so I am assuming that is free. I have read there is a valve on the oil filter flange though any idea where that is? I guess it is time to roll up the sleeves and open the valve cover and start digging. I am gonna price a rebuild. And weigh the options. Thanks guys I guess you have take me as far as we can together now the call is mine I guess.
You should change your oil feed for the engine which will get you rid of this problem