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

Tnx, you are right, PRH, I did not see that was the case until the OP's last post. Oooops.... Sounds like he is all set with his pressure now.

Your point about the metering in the lifters is on the mark: If there is a limiting upstream restriction setting the flow rate, then what goes on downstream (at the rocker in this case) does not set the flow.