727 Transmission for my 1974 Plymouth Duster

Rebuild the 904 with good parts. Replace the backward wound spring in the front clutch with the ati spring.
The 904 has a riveted Sprag in it the 727 has a pressed in one.
There is less parasitic loss with a 904. In other words more engine power gets to the rearend. Should be good to at least 600 hp.

ATI Racing Transmissions - Chrysler Torqueflite TF904 Drag Race Transmissions