Originally Posted by Cab_Burge
Do you remember how much oil pressure it had with both pumps above 4500 RPM? Is that information on your dyno sheets? scope
I have had to trim a lot o the black high pressure bypass springs to get to have 65 lbs. at 6500 RPM with 5w20 wt. oil in my street motors at or above 130F oil temps.
I think I saw a small HP and torque gain by cutting the pressure back on a high volume oil pump on one of the dyno tests done years ago from 80 lbs. at 5000+ RPM down to 65 lbs. at 6500 RPM with the oil temps above 150 F, maybe 3 HP, maybe less confused
I've never had a bearing problem with 10 lbs. per 1000 RPM rule on any motor with loose bearing clearances, I have seen rod bearings spin in other motors at the drag races that had less than .0020 rod bearing clearances on BB Mopar motors when raced with cool oil temps work


Do not have the Dyno sheets, long gone. 3 military moves and 2 house moves since then. This was when 513's were not common and Fram filters were GREAT. It was an imploded Fram filter that killed that 513. I don't play with big blocks any more.

I am going by memory. All dyno runs were at 180 degrees F water temp. I think with the 20W50 and HV pump it was north of 100PSI at 2500-3000 RPM and 80 PSI with the stock oil pump. With the 5W30 HV pump I think it was like 60 PSI and 50 PSI with standard pump. We did not play with the bypass spring at that time. We did grind it down some later to get closer to the 10 PSI per 1000 RPM.

Over the years I have always blueprinted and ported all oil pumps. Most oil pumps have too tight rotors, small passages and lots of bugers in the ports.

Retired, US ARMY 1973-1994
ASE mechanic, Electrical 1994-1997
Retired GTE/VERIZON/FRONTIER 1997-2015


Posting cheap tech help (CRAP) here since Nov 97, 1000's of posts, some may be good.

03 Suzuki Burgman 650(Burger King) Scooter
65 Formula S Cuda
78 Little Red Express Truck
98 Buick Regal (wifes car)