This has been a very good thread.
I will add a half a picture of the fitting used by the Canadians that acted to block the other way while it was being used, and allow normal flow internally through the block when no external fittings (cooler, filter etc) was not connected. This is the one Barlea referred to.
I will show also a picture of the circuit diagram showing a cooler, a bypass valve, and a filter, from a Canadian Ford (Bren)Carrier.
One confusing aspect of this thread is about the two types of filtering systems used on these fords.
The original canister type is a bypass system that bleeds off about 5 to 10 percent of the oil, to filter it, and return it directly to the sump.
These filter elements were a very fine filtering media that removed very fine particles. They had a large surface area, and the oil supply to then was limited by the restrictor. They could stay in service for a long time. The rest of the oil being used to lube the engine before its return to the sump.
The full flow systems (95 or 100 percent.-two variations) used a modern type filter where all the pumped oil is sent through the filter, then goes on to lube the engine before returning to the pump. The variation between the two full flow systems is this.
In the 95% system the oil going to the rear main is not filtered before it goes there. In the 100% system it is.
The 100% system requires much modification. The 95% system requires very little, and what you need to keep in mind is that it(the oil) is already pretty clean as there is a 95% chance it went through the filter before it was picked up by the pump, this time around.