High Volume vs Standard Volume Oil Pump

It's a bit of work, on most engines, but the best way to see if you <NEED> a high volume pump, is to see what oil pressure you have at about 4-5,000 RPM. Then increase the relief spring pressure. If the oil pressure is now higher then it was before, then the stock pump has enough volumm. If the pressure did not increase, then the stock pump does not have enough volumm. This is easy to do on a big block or slant six, since they have external oil pumps.