RPM and stock 360 pan
Find a picture of any Ford Cleveland engine. 351C, 351M or 400. Look at the intake valley. They need all the oil drain back help they can get at sustained high RPM. Yes, I think with an HV pump and stock pan only running 5 quarts, they might pump the pan dry.
By stark contrast, look at any of the older pontiac V8s. They have so much drain back area, some of the lifter bores are hanging out in no man's land. In fact, it's a common failure on high RPM Pontiac V8s to actually break lifter bores off because some lack good support. But they don't have trouble with oil drain back. lol
