My best advice Robert, if your skilled/equipped to machine/fabricate the trany case and assorted parts,....then go for it,.....the Ford tranny will require mods to the case, to get it in the A body....or mods to the floor and torsion crossmember to fit the Ford tranny unmodified, shifter location on the Ford will be rearward, way rearward, if that dosen't matter,.....Keisler has a lower cost T-45 Transmission kit (5spd- from 375-425 ft lb units) avaliable starting at approx $1400 up should you want to install a fitted, new transmission
Mike
here's a Keisler A body install of a TKO 600 in a 69 Dart with the floor removed