The 10 psi per 1000 rpm is from the Buick "folklore". It actually depends on the diameter of the crank, since the centrifugal force varies with the radius. Bigger cranks may require more than 10 psi per 1000 rpm. The journal bearings are "hydrodynamic", in that the turning crank provides the pressure once the oil actually gets where it is needed- oil pump pressure is no longer involved. That's true in top fuel, and in an econobox.
One issue with higher pressure on the Buicks can be side clearance between the rods. That dimension, along with rod bearing clearance, controls flow that splashes onto the cylinder walls. Years ago, you could get new rods that were "thicker" than stock, to let you set that clearance tight, if you wanted to. Now, that dimension may be too big, and with a high volume pump, you might get more oil on the cyldinder walls than the rings can handle. Seems possible, anyway.