JeremyAnderson

Supercat is dead on. One thing that I like to see on wet sump engines is external drain backs. A -10 or -12 from the rear of the heads to the pan works well. The drains give a path for the oil to drain and a place for the blow by to move from the crank case to the valve cover breather.
I've seen engines that had compromised ring seal starve for oil becuase blow by kept the oil from draining to the pan.

mikes280

a little story , when i built my blown 540 it did the same thing . I had a 10qt KE oil pan on the motor and it comes with it's own pickup. Well i hurt the motor ,#1-2 rod bearing and i was convinced it was a drain back problem, but i was going to check everything so while the crank was out of the block i mounted the rear main cap with pump and pick up in place , i set the pan on and shined a light in the block and liked to hit the floor. the pickup was 7/8'' off the bottom of the pan , this pan has a wide sump in the rear so i set the pan upright and started pouring water in it 1 qt at a time untill i was at 7/8'' , it was almost 5 qts. I called KE and they said no way so i took a ruler and placed it in the block and took a pic and sent it to them. You would think a $800 dollar pan would come right but mine was off and so was a lot of the pickups they had in stock , they sent me a good pick up and problem is gone , i have turned the motor over 5000rpm for as much as 10 miles without a problem .Bottom line i had about half of my usable oil for the motor and the rest was laying in the bottom of the pan. Don't know if this will help you but it is worth looking at.