Pumps do not make pressure, pumps create flow. The passages and restrictions create pressure.

Melling and many others sell HIGH VOLUME pumps.. the gears that move the oil are longer giving more displacement per rotation.

So yes, you can get a high flow pump and increase the system pressure. It won't lube any better, and may actully be detrimental as some parts are splash lubed.. to much pressure may alter that.

Typically 20-30% GPM flow increases are what you find for high volume pumps.