The 904 in the 74 Dart will work in your Barracuda. If you are keeping the 273, you will need to get the center hub of the torque convertor in the 74 model 904 turned down to fit in the end of the 273 crank. The hole in the tail end of the 273 crank is ever so slightly smaller than the hole in the tail end of the 318 crank. It's an easy fix, but will make you :banghead: if you find out at the moment you're trying to bolt the transmission up to a 273. Been there, done that...pitched the cuss fit! LOL Good luck.