Never like how little oil there is in a Stock Oil Factory Pan. Even a stock pump can empty a Hemi pan of 6 quarts and put it in the valve covers and lifter gallery. The Hemi I have in my Challenger all factory iron 426 has around 100 lbs of oil pressure at start up, 40 lbs at idle. I run around 12 quarts of 40 weight oil. In one motor on start up it pegs the gauge to well over100 lbs to about 150 lbs but dont go by that it is big cube Hemi all aluminum with a Barton spray system and all kind of good stuff. I am a big believer in oil pressure as long as you have an oil pan that has 10 or more quarts. One motor that we had built by another Hemi Builder that ran a Funny car for a family member had low oil pressure at start up and break in. It was like 11 lbs at hot Idle. 70 lbs at start up. Changed the pump and other stuff no change. Looked at everything and finally pulled the hemi and took off the oil pan and saw some numbers on the pan rail the we thought would answer all the problems. Stamped on the rail was 1.5 M. So out comes the crank and measure it and the mains were down 1.5 from the factory. Back then and likely now you could not find an over size main by 1.5 or 1. So we get out one of the spare stock cranks 10 under and put it in the motor and that solved the low oil pressure problems.We just got luck noticing that stamp on the oil pan rail or the complete fresh motor would of been torn down to bare bolts. Motor is still in the car for the last 35 years.