If the holes are 1/8" npt then it was a bypass setup. If the holes are bigger it would be full flow. Some Canadian trucks had the same setup as the U.S. engines (big oil filter lines, water pump with extra outlet and big thermostat housing) The hole that gushed oil goes directly into the main oil galley so it will gush no matter what oiling setup it had. Anyway there were both types of 261's in Canada.
Curt B.
