Following Forked and JD is hard, But they reiterate the oiling problems. They are great and know their sheit.
First, oil restriction isn't the problem, as I understand it. Built a few Pontiac 389's and 400's in the day. The problem involves machining larger oil passages to the mains and rods, then , maybe in extreme conditions, restricting oil to the galley area. THEN, doing away with or modifying the spring and oil bypass near the oil filter location.
Back in the late 70's and early 80's, such work could be done by High Performance Pontiac in Hawthorne, Ca. But wasn't cheap, as I recall. They were pretty proud of their work.
Then Again, I repeat, gonna hot rod it, leave the olds alone, and change powerplants. You'll thank me later.
But gonna use it as a cruiser and family skier, leave it be, but know it's limitations.
Ray