Swap A833 for Auto - 71 Duster 340

2 big issues to consider.....

GV price....they have really gotten up there, I think exceeding $2500
modification....to maintain the factory engine / transmission angle, modification /enlarging the tunnel aft of the transmission cross -member is required

if it were me.... I would go with the bolt in 727 swap and change the ring and pinion for what works best. Of course, I would also have a (bolt-in) 8-3/4 and several pigs....street, highway, strip. In my day, the early 70's, we would change pigs in a NY second for a $10 street race.......we called it, instant RPM.