The internals of BB and SB 727's and 904's vary with the engine power, any of the 727's listed would be a good core to build with the '72 being first on the list.
A 904 from an early 318 might be marginal with a built 340 but a later 998 or 999 would be just fine.
With the torqueflight transmissions, there are a few differences like John mentioned above. Any can be built to the same level by changing out some parts.
With the 727, any of the '67 and up are a decent choice, before that the input shaft, converter, front pump are different, and pre-66 have the rear pump and cable shift.
Most high performance 727s use the 1971-up front pump and drum with the wider drum bushing. Some have a drum with the retainer clip machined for 3 clutches, where the high performance cars have a drum that accepts 4 clutches.
There was also the 5 clutch Hemi drum. In most applications the 3 clutch unit will be fine. I ran a stock 4 clutch unit in my 12 second 4,100 lb Charger for years. The front aluminum gear splines did look like they were on their way out when I re-built it for the new engine. The 904 is also good if built correctly and it takes less power to run. With any transmission, proper assembly, a trans-go shift kit, and a trans cooler go a long way in making sure they last a long time.
