All Ford Canada blocks from about 1940 until end of production in '54 have the inboard vertical passage already drilled and tapped for the military full-flow filter and post-war civilian full flow option that was available until end of '51. The military and post-war civilian option used 3/8" ID hard lines and the 8BA type used 3/8" flexible lines and a larger filter. The horizontal passage was blocked with a special fitting used on the outboard vertical passage that had a permanent thin brass 1 1/4" long tube on the bottom. The tube was long enough to block the horizontal oil passage and allow the pressurized oil to flow to the filter and back to the inboard passage. The brass fitting adapted the 1/4" pipe thread (3/8" ID) to the 3/8" ID hard or soft lines to the filter. If the filter was removed for any reason, the special fitting would have to come out to plug the holes or adapt back to a bypass filter, and no possibility of a plug remaining inside to block circulation. Use of the special fitting meant that the option could be installed easily at the dealership or removed without leaving a potential blockage in place.
No drilling or enlarging of internal passages was necessary. Since the oil pump is a gear drive, metering pump, the same volume of oil is pumped for each revolution of the engine. If a high volume pump is used, the internal passages are still of ample size to pass that volume of oil, so it's doubtful that either pump would be putting out more flow just because the passages or external lines were opened up beyond the 3/8" used by Ford engineers. ..B.