[DavidG]

Charlie,

That's a good question, but a good answer is perhaps elusive as an evident error exists on the original engineering drawings for the dimensions of both the B and 18 torque tubes and drive shafts as discussed on one of the earlier threads cited above. (Or maybe the reader [me] misread the drawings.) One of these days I will have to go back to the BFRC and find out if it was them or me.

I seem to recall something about the B driveshaft being shortened a small fraction, but I'm away from my car stuff so cannot verify that.