Boarder Line Low Oil Pressure

Hey, I just saw this post, I posted the same exact issue in another thread. 60 psi when cold, but after its hot, down to like 10-12 psi. Mine is a freshly built crate engine, 360 magnum. The builder suggested that for a stock oil pump that is within spec, and if I wanted to, just swap from 10W-30 Lucas Hot Rod oil to 20W-50.
Brian