What is being seen here, is that a high volume pump isn't needed on a freshly machined motor.

The clearances are tighter. A new stock pump will move more oil, and make more oil pressure than you can ever use.

I recently reringed a 440, and put fresh bearings in it. No machining, and the clearances checked to be around .002 to .0025 on the mains. .002 on the rods, and cam bearings were not changed.

I used a stock oil pump.

The pressure relief stuck in it at start up, so it was full pressure.

It made so much pressure at an 800rpm idle, that it pegged the gauge and wrecked the sender, and BLEW the filter right apart.

SO.... in a motor with high clearances (compared to an actual rebuilt/machined motor which would have main clearances closer to .0015) and only a standard volume pump, it STILL moved enough volume of oil, to make enough oil pressure to destroy a filter, at only 800 rpm. I'd be surprised if it was anything less than 100 psi.

All this said, I'll never buy a high volume oil pump again. At least not for a fresh motor.

I'll gladly put one on a motor that is miled out, and has oil pressure problems.