[browke]

I'll add some more to the 'BB' mystery. I have a 1940 01 pickup that I purchased from the original owner. The original title came with it. I've attached a photo of the top portion of the original Nebraska title that shows the "Motor No." starting with 'BB'.
Note: I blurred the last few numbers from the Motor No. in a photo editor just because I'm not sure how prudent it is to post a photo of the unedited title.
The numbers stamped on the frame and the bell housing are identical to the number on the title but do not have the 'BB' prefix. It's just *18562XXXX* (I've omitted that last 4 digits).
The truck has the original V8 engine and original 3-speed trans.
Does this help clarify what the 'BB' prefix means? It doesn't seem to match up with the suggestion that BB means a 4-speed trans. Since the 'BB' prefix doesn't appear on the frame, it must have been copied from the Mfr Cert.
Any ideas how to interpret the meaning of the 'BB' in my situation?