Posted by Gypsy Jim (IP: 24.4.252.68) on October 26, 1999 at 01:18:57:
In Reply to: Oil pump question posted by Brian on October 25, 1999 at 23:30:54:
A high volume pump is just that. It will "theoretically" pump more oil out of the oil pan and into the engine. In a stock engine, with standard bearing clearances, a regular pump will produce an appropriate amount of oil flow at about 38 lbs of pressure. If you increase the volume being pumped through the same oil galleries and clearances by 25%your oil pressure will be higher and the stress on the drive rod to the pump will be higher. For most street applications, the standard pump is more than adequate.
However, since you say you have your engine apart, you may want to make some changes which will then neccesitate a high volume pump. With a high volume pump, it is possible to pump the oil pan dry under certain conditions (not a good thing to do). Things to do to prevent this include: opening up/radiusing the return ports in the corners of the heads (that gets the oil back to the pan quicker), installing a deeper oil pan (that creates a bigger reservoir), and the most important thing in my opinion, opening up the oil passages in the main bearings (this gets more oil to the bearings and thus back to the pan). This last item should be done on any SBF rebuild as it insures adequate oil on the main journals of the crank. If you do this modification to the bearings, you have to install a high volume pump in order to maintain the proper oil pressure.
One other thing... be sure to replace the drive rod with a good aftermarket rod. I use the Ford Motorsport rod myself.