[Darrin Wright]

Lynn,
having read the 1943 workshop manual, it describes the 1940/41 engine as having a slinger on the crankshaft and the seal reatiner fitted to catch the oil.
On the 1942 engines (and earlier engines fitted with a later model crankshaft) the slinger is machined off and a different seal retainer fitted with a rope seal to keep the oil in the sump.

I visited and joined the fordbarn website/forum and have posted a question there to see what info I get.

I think I have the earlier crankshaft and rear main bearing and do not require the rope seal, the slinger should do the job. At this point in time I will not modify the engine as what was engineered originally should work well providing I put it back together correctly or as originally designed.