Unless you also have the output shaft for the Saginaw that mates with the B-W overdrive unit, you've got a very expensive paperweight. It's not going to be a simple matter of installing the OD onto a run of the mill Saginaw 3 speed. There might also be a difference in the main transmission case, like there is with a SM-318 and a SM 319 Muncie. As far as cobbling up something to make the OD a manual shift, good luck. There are some very good reasons for all the electric controls, mostly to prevent damaging the OD or the transmission by accidentally having the OD engaged at the wrong time and/or speed. OD-equipped Saginaw boxes are VERY scarce, and they're priced accordingly.

I don't think I've ever heard of mating a B-W OD to a 4 speed transmission of any sort.
Jerry

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