The AOD should work. I am not sure if the cougar used a 28oz. or a 50oz. flexplate though so you will need to make sure on that before using it. Also is the cougar console or column shift? If it is column shift you will have to flip the linkage.
Yeah, if it has a shifter ROD, you will need to bend it a bit.
The mustang shifter arm points DOWN and some of the other mercuries and such points UP. The pattern will be reversed.
ALSO, some of the AOD's have one less direct drive clutch. Also....some might have the "C" servo, which isnt nearly strong enough for racy applications. C servo usually indicates one less clutch, btw.
if it was from a 5.0 queergar, the tranny will be nearly identicle, will have a lower speed governor, and the shifter lever will be wrong, get a stang lever.......the vb must come out to do this..... might as well put a shift kit in it. b&m sells the stang lever by itself, and has a cheap shift improver kit that a monkey could install in less than an hour......since the vb has to come out, might as well spend the 25 bux on the kit.