Lots of write ups on the web about doing this swap. Depending on your engine mods, a stock T5 is good, or a TKO 500 or 600.
I am still working on my T5 swap in my 69 Cougar, and just found out that the tubular cross member I bought from Mustangs unlimited isn't fitting right. I may be able to get away with just enlarging some bolt holes, but for the money, the ing thing should just bolt in!
the aod has good potential, but it stock form its a power sapping pos...try throwing a shift kit on it, manual valve body, and some 4.10s in the back..I think youll be pleasantly suprised
Actually the fix in my case, was to grind the round "ears" off the tabs. Spent 10 minutes with a grinder, and it then did bolt right in. Still, for the money, kind of not happy about it.