Farmall Cub

Here is your answer. Check the first 2 listings for reference 6. Two different crankshafts.

The first listed, for the early rods, is 251264R1.
The second, for the late rods, is 527456R1.

Thanks, Jim, that confirms it. what TC37 revision was that in?

It was in ENG-1 Engine Parts Catalog Section A C-60 Engines. Rudi only has Section A on the server, no date/version of ENG-1 showing. He may know what revision it came from.