Where did the myth originate that pumping the oil outside the engine, through a filter that's designed to strain out rocks, marbles, and medium-sized boulders, then back into the block, before getting to the parts that need to be lubricated is somehow better than sending the majority of the oil directly to the bearings?
Until somebody comes up with a way to adapt a higher-volume oil pump to a stovebolt engine, I question the necessity, and/or the wisdom of doing the "full flow" modification.
Jerry