When we build the big stroker windsors we use a girdle on the main caps for added strength. I think quite a few of the builders do. In order to do this the
oil pump must be clearanced for fit. I have seen a few
oil pumps that had a little too much clearance and they actually cut into the galley. This will cause air to enter the pump and cavitate resulting in lower pressure. We just had a 418 windsor built by a well known shop in here for low
oil pressure at higher rpm. It would run 35lbs at idle and never get above 45lbs at any rpm. The builder replaced the pump thinking it was bad and did the same thing by clearancing too much again. We fixed the problem and had 45lbs at idle and 70lbs at 6500. Just something else to think about.
We always run a 20w50 racing oil in all our engines after break in. We break them in on 30w. I hate the sound of a hot engine running 5 or 10w30. It seems to thin for me. The racing oil works great.
Don