74 dart swinger interchanging?

I do not agree on the brakes. I believe there is a different spindle, caliper and ball joints on the 74 Dart as compared to your Barracuda. You would have to change the upper control arm, and swap on large bolt pattern wheels. I am not sure if you'd have to change the lower control arm as well. In my opinion, thats a "do able" swap, but not a bolt in, as it requires changing much more than just the rotor and spindle.

If you aren't worried about keeping the 67 stock, it may be worth swapping the entire set of running gear over, front and rear.