I'm no expert on fluid dynamics, but if the pressure is ok then the volume must be fine or the pressure would drop off. Ok, lets hear from the board engineers on this
Some Chevy builders have used GMC pumps , which have longer gears and more volume.I have used Mellings and Sealed Power pumps, they had the same size gears as whatever pump was already in the engine.
Running oil psi higher than necessary for proper engine lubrication only serves to waste power, heat up the oil and stress out the pump drive.Of course the trick is to know the minimum pressure your engine needs.
Small block Chevy guys like to install a high volume pump, like Chip says they beat up on the pump drive gears.Back 20 years ago, before drysump oiling became common on circle track engines,350 Chevy engines devoloping 600 hp at 7500 rpm back then could survive a 300 mile race with as little 60 psi, using a stock Z-28 oil pump.Generally, engines requiring high oil pressure for survival, have a poorly designed oiling system.
And to make Chiphead more nervous, certain types of cams cast iron or billet each require distributer gears of the proper metal for long life.
