New to me Barracuda with Mopar Crate 390hp low oil pressure

I’m not sure you two are on the same page(or maybe it’s me who’s on the wrong page).

I thought the engine being discussed here is a Magnum.
Magnums pushrod oil, and the metering to the top end is controlled inside the lifters.
Whether it has oe or roller rockers won’t really affect the pressure, or how much oil goes to the top end.