B&C Alternator - Auto equivalent form factor?

I have a B&C Model BC460-H alternator and would like to know if there is an automotive replacement for it in the case of a failure away from home. I?m looking for the exact form factor that would allow me to go to an auto parts store and purchase one and replace the faulty B&C in order to get me home. This model uses the B&C external regulator. I used to run the auto alternator (Suzuki I think) but decided to replace it with the B&C when I upgraded the panel for IFR. The old auto alternator isn?t the same form factor and wouldn?t just bolt back up. Has anyone else thought of this scenario? Thanks David

Or better yet just install a B&C backup on the vacuum pad and then you don't have to worry about it.