Are A body and B body radios interchangeable?

The interchange is '65-6 Barracuda and Valiant but I've swapped others in those cars with no major problems. Sometimes the rear support anchor is in a different spot so you have to make a custom strap to hold the back up. I don't remember having done your exact exchange so there may be something to keep you from doing it but I rather doubt it. The basic radios were real close, they mainly changed the knobs and faceplates.