I have always had this problem with my single line setup. Both static and swinging pickups. Had the line above the pump, below it. Run a 51515R wix filter with a drainback. No difference.

I have an accumulator so I never worried about dry starts but when I change oil I have to pull the distributor and spin it at high speed and it still takes a bit to pick the oil up.

I need to go through it next oil change and check some things mentioned here. Because priming it every oil change is a PITA.