With your combination you're pushing your luck with a stock block. Be it B or RB. With vertical lines I would say something that shouldn't be there is floating around. If you don't have a good oil pan with baffles and good windage tray. That contains the oil around the pickup. I would predict spun bearing.
I have a main girdle and windage tray. the oil pan is a milodon 7 quart with baffles. As for the the pick up, it is a swinging single line external pick up. When warm I had 70 - 80 psi. The vertical lines are not deep just that I can see them. That was my thought also that I have a bearing that has failed. The oil came out as clean as when I poured it into the engine. I even filtered it as it was drained out. Nothing in the filter either.
Digger73 (Mike)
