Radiator and Oil Pump Replacement

[Showme-K-20]

My 89 GMC K-1500 does the same thing on oil pressure and it has 186,000 miles on it. I was going to have a new oil pump installed and my mechanic talked me out of it. He said my motor was just getting broke in. I'm planning to run it till it quits and then buy a new crate motor.
The plastic radiator went to leaking shortly after I bought the truck, and the best deal I found was on Ebay. There is a shop in Oklahoma that I dealt with. I could have bought a direct replacement, but opted for the all brass radiator instead. Haven't regretted it.
Bob