All the oil flow in the world won't keep your bearings alive unless there is a restriction at the end if the system so that pressure is generated. That said, the flow rate has to be sufficient to replace the oil at the bearings before it gets too hot. Pressure measurement is the one most important variable to watch, but the oil pressure gauge takeoff needs to be after the filter, cooler. and whatever else you are cramming your oil through before it hits the bearings. High volume oil pumps will cost you HP, heat up the oil more, and cause more wear on several components. If the standard volume oil pump gets it up to 45 psi you are fine. The fact that you have pressure means that the volume is sufficient. Any more volume after that and all that volume is just getting blown through the bypass in the pump. That bypass route adds heat to the oil.