Hi rusty,
I have also read somewhere if your bearing clearances are in limits in regards to your crank and rod bearings, then using a high volume oil pump actually kills HP, simply because the bearing clearances are a "metered leak" based on what the factory engineers determined it needed it to be.
By running a hi volume pump in an engine with a new or cut crank and new bearings equalling tight clearances, the high volume becomes high pressure at these controlled leak points, and actually makes the crank and rods "tight" in the bearings under load with higher oil pressure requiring more horsepower to turn the crank.
A hi volume pump does have its place for instance, in a clapped out V8 with low oil pressure because the clearances are out and you dont want to rebuild it. A hi volume pump can be used as a bandaid fix
