Mustang Brakes?

You are right, I would not mess with 9" brakes. Big bolt drum knuckles are not A body. I would first decide whether you want big or small bolt pattern for the Dart. Run with the 9 " drums till you get everything, then do your swap. Also consider what rear. Having 2 different patterns is a lot of trouble. I'd also not believe what other people say. I'd go out and look for myself. If you want small bolt pattern, I have a set of 10" front drums knuckles and all you can have for $100 + shipping.