Hi volume oil pump vs standard volume pump

I run a hi volume pump in my 340 with a moroso 8 qt. pan and their rectangular screen pickup. I would not run a hi volume pump in some other makes with a stock pan. my friends 327 with a big cam and a stock pan and a hi volume pump and 4.88 gears on a 1 mile blast down route 18 showed zero pressure on the gauge. we pulled over and everything looked good. the pickup did not fall out. we waited a moment and drove away. later he went 12.5 at epping