An HV pump will pump more oil and, all other things being equal, will put out more pressure.

However, if the oil pressure relief valve opens at, say, 60 psi, and your standard pump will give you 60 psi at cruising speed (or higher), then switching to an HV pump won't give you any more peak pressure; all it will do is funnel extra oil back into the pan. It will give you more pressure at hot idle if that's important, and if a stock pump only give you 10 psi at hot idle and the HV gives you 30, you might want to switch.

On the other hand, if the standard pump only gives you 40-50 psi max (with a 60 psi relief valve), then switching to an HV pump will increase oil pressure at higher speeds, not just at idle or low speed. And in a motor with large bearing clearances, this may very well be the case.

Whether the HV pump will actually increase max pressure depends on the relief valve, bearing clearances, etc. And whether you need or should want more pressure depends . . . .