The life of this thread has surprised me a bit but I think it is because
oil systems are a bit of a mystery. We all add the items common to the Cobra mystique (new distrib maybe MSD +
oil cooler + roller rockers + and maybe a roller cam) AND RACING
OIL VERY OFTEN, OR A HEAVY WEIGHT OIL.
If a STOCK engine other than the add ons, if the roller cam was stock but upgraded to more getty-up then it is still basically stock. The oil system needs to be balanced to the system. If all is stock then a stock pump with close attention to the oil weight and compatibility of cam/gear is fine. Oil temp is a major thing to get overlooked and often is run WAY to cold. The start up or warm up time is overlooked by many in addition.... come on guys are you always letting her come up to full temp before zinging the RPM ?
As an Ex- auto machinist, drag racer and parts store counter guy I saw what was killing engines all the time. I am talking in very general or stereo type terms here so bare with me a little. The average stock engine does not need 50 W. racing oil and way too many coolers out there without thermostats to control minimum oil temps. Ford's oiling system design does not have a high pressure bypass in the oil filter also but has only 1 at the pump body. Many stock oiling systems have a cooler and a remote filter added to them in a series configuration rather than a parallel design increasing the total restriction. This restriction forces the pump to push against this higher restriction to the point of bypass in some cases. If a T-stat is used then only hot oil would be sent through additional restriction of the cooler. Time to reach the oils minimum temp is also greatly reduced with a T-stat.
Low gage pressure is easy for all to see but the addition loads or wear from high internal pressure is not visible to the driver. As a driver all you can do is (in this order) verify the oils minimum temp is met and then the max is not exceeded. Run the lightest weight oil possible to not violate minimum oil pressure when hot and at an idle. If either of these are wrong then the engine design needs work.
I run modified clearances on all my Toy engines learned from past builds and these larger clearances are to remove engine heat and make parts live. Oil splash from these bigger #'s is also worked on inside but in the end it is still up to driver to watch the pressure and temp's to prove design is correct.
A high volume pump is not to intended to increase oil pressure but rather maintain the needed flow amounts to reach the minimum system pressure. The manufacturer sizes the stock pump to a stock need, it is only when demands for size or flow increase that a hi volume pump is intended to be used. The catch is many have increased the needs or want a little reserve over factory bottom line design. More damage is caused by to heavy of an oil and being to cold than inadequate flow in my experiences.