Nick here is the answer to you ID question. The Borg/Worner will have a number on the tail shaft that is R10H-1A this one has the non-syncro. first gear. The one you are serching for is the Saginaw which has the tail shaft # R10Q-1A. The Saginaw will have a tailshaft with a 27 splines while the Borg/Worner has a 16 splined shaft.
Hope this helps and good luck in your search.
