Truck Repair: excessive oil pressure, gmc s15, cam bearings

Question
I have an 87 gmc s15 with a 2.8 v6 the engine was recently rebuilt by a shop that is now out of business. It had so much oil pressure it broke the collar off that holds the oil pump drive so I tore it all apart to see if any of the oil passages were pluged and if any cam bearings were spun everything appears to be ok.  So I put a new oil pump in and it still has too much pressure 50psi while turning the pump by hand. I checked the oil pressure relief in the pump and in the oil filter housing 2ea. all move freely. this happens of course when the engine valve train is completely assembled.  Could there be a plug put in wrong in the lifter galley?  I appreciate anything you can help with Thanks  

Answer
Hi Chuck,
Not my area, but I wouldn't expect any cam bearings to spin, although I would want to check rod and main bearings.
The cam bearings do have a hole in them that needs to be ligned up with a hole in the block for oil to get through.
Same goes for the rod and main bearings.
The relief valve in the filter base, I believe, is a plugged filter bypass, not a pressure relief.
Now I can't immagine 50 PSI breaking that collar...it may have been broken during assembly. The pump itself should be capable of pumping several hundred PSI, and the 50 is the pressure that the relief valve opens to keep from bursting the filter, or blowing out freeze type plugs.
I would check those bearings, put the pump in, and see if oil is getting to all the rocker arms, and probably let it go with the 50. I really don't think that is all that high for new, cold oil, with all new bearings.
I'm mildly curious how you are turning the pump by hand with the valve train assembled, and what you are measuring the pressure with, and how accurate it is.
Van