99' Intrepid oil pressure problem after engine rebuild

Hello,
I am having a oil pressure problem and I don't know much about cars. I had to have my engine rebuilt due to the motor seizing up tight as a drum. I had a friend that is a pretty good mechanic rebuild the motor for me. It was a 2.7L. He replaced the oil pump, water pump, new crankshaft kit, the whole nine yards. He got it all back together and it started right up no problem. When he went to drive it around the block the oil light came on so he stopped right away. He said the oil pressure would drop very low so to be sure it wasn't the sending unit he bought a mechanical pressure gauge and check with it and sure enough the brand new pump was losing pressure after the motor warmed up. He purchased another new oil pump and installed it and the same thing happens. He was lost so I towed the car back home and am now wondering what might be causing this pressure problem since I wouldn't think that 2 brand new oil pumps from the dealer would be bad. Any help with this or suggestions would be greatly appreciated and the sooner the better. Thanks.

The new crank might be no good.My father has ran into this after taking one to an auto machine shop that checked it with a micrometer and was under specs.

I would check what the crank was turned to and check if they gave you the correct bearings. I did one and they gave me .001 bearings instead of .010 bearings. I use a tool to prime the pump using an electric drill and I could only get appx.5psi. Start here and if correct mike the crank or take it to a machine shop.