727 -> 904

I agree with Guitar.

The 904 advantage is in the low - cost low gear set, and a little less rotating mass, but on the street -- I would take the 727.

I have a 1971 Duster 340 that currently has a 904, and I just sold a 1969 340 Dart Swinger with a 727.

Looking at the 727 on the bench with the factory service manual, the 727 has much more surface area in areas known to take stress, clutch packs look different on the 727, bigger beefier parts overall.

The 904 looks OK, but I see no real performance gains with the 904 over the 727 at the strip.

Always keep in mind that the torque converter has a LOT to do with overall performance (stall speed, flash, etc.).

For my money give me the 727...