differences in 727 transmissions

The small block bells are kinda flat on the pass side while the big blocks are pretty much round, the big blocks have 4 little 1/4 20 threaded holes for the dust cover. The later model the better usually, Chrysler improved and strengthened the 727 as the years went by.... for the most part. Stubby shaft truck units have many good parts- you just need to change the output shaft and extension housing. I would rather start with one from a 78 pick up truck than one from a 69 road runner. Most 1/2 ton 2wd truck trans will go right in a car with no mods.