67-69 Barracuda 8.25"

904 is the automatic trans behind the 273. The 8-3/4 was standard with any engine 340 and bigger (hemi four speed cars had a Dana 60). By 1967 many 273 four barrel auto cars got the 8-3/4, too. My old '66 Barracuda (Commando 273/4 speed) had a 3.23 geared 7-1/4. The previous owner broke two sets of spider gears and one axle. I was braking from 10 mph one night when the other axle broke. I swapped in the 8-3/4 from a '67 Dart GT rallye package car.

I wouldn't run a 7-1/4 due to it being weak, too weak in my opinion. Especially on one that is 50 years old. I broke that axle in 1981...