Pull the oil pump bypass valve out and make sure it has a small block valve in it (with several holes in the spring cup part) and not a BB type with no holes wrench scope
there was a bad batch of new Melling's or the other manufacturer years ago that had the wrong bypass valves in them whiney rant puke scope

Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)