A question I should of asked before

The B body axles need to be 28" long after shortening. They are tapered near the splines. If you do not have at least 28" from the outside of the flange to the beginning of the taper, then they won't work in your application.
There were several different width b body axles over the years. I had C body 8-3/4 axles shortened and resplined by Moser. Both measured 28" and fit my A body housing.