I ran 5W20 WT standard non synthetic Valvoline that Wal Mart stocked in my old pump gas Duster, it would have right at 18 to 20 lbs at 850 RPM in gear with 180+ F oil temps., 30+ lbs at 1200 RPM and 65 lbs. above 3000 RPM with the same oil temps. That motor made 727 HP and 700 + Ft lbs. on pump Oregon 91 octane pump gas the last time I had it on a DTS engine dyno with that oil and oil temps. I would shift the motor at or a little above 7000 RPM with 65 lbs. pressure, no problems with the bearings or any other parts in that motor, solid roller cam with full time oiling to the Harland Sharp roller rockers with a .040 restrictor to each side 250 Lbs. pressure on the seats and 650 lbs. open pressures
Lots of myths on oil and every other part found in our Hi Po motors, not every one agrees on any of them