Fox boddies have a different radiator?

I don't know about the fox radiator being different, but the autos are different because they have a tranny cooler or something like that. I have neither a fox, or an auto, so I don't know much, but free bump for ya.
 
Fox radiators are 2 row copper/brass stock, whereas SN's have a one row aluminum unit which is like 3/4-1" thick.

The SN has a tiny radiator because of the snout and accessory packaging.

FWIW, you can use a radiator for an auto - just plug the tranny heat exchanger lines off. It will not appreciably affect the cooling ability.

I would not really want to toss a copper/brass radiator in a car which came with an alum radiator.

Good luck.