In my case the point is moot, because as of right now we are running a bone stock 1974 T/F-727 in the supercharged Dart.
I know it isn't ideal, and yes I mean bone stock. Pulled the engine/transmission out of a 1974 Dodge truck and put them in the car (1972 Dart).
Then we slapped a 144 B&M supercharger (on top of a slightly modified Holley street Dominator aluminum single 4-bbl. intake manifold), 750 cfm Holley carburetor, my buddy sold us a gently used reproduction 340 camshaft/matching valve spring/roller timing set for $75.00 and we installed the brand new set of Hooker Competition headers that came with the car when we bought it. The car has electronic ignition with a cheap Accell Super Coil.

Anyways my dad wants to race it a few times this coming year so we were looking at building a good transmission for it. He is a transmission rebuilder by trade, but hasn't built much performance stuff.
I just figured if a 904 is "better", that's what will be going in the car.
Either way we have to buy all the parts and a converter for either transmission.
I'm also not a big fan of having to put out money for the billet drum in a 727.