1974 dart 4dr Questions

As said before, any a body '73 and up if factory equipped with disc brakes will have the bbp 4 1/2'' brakes, unless someone changed them for some reason. It looks to have the bbp front discs on it just by looking at the pictures.
Being a slant six car, it must have had power brakes from he factory too. Any V8 car in those years had bbp disc brakes as standard equipment.
Do yourself a favor and get all of the front suspension pieces from that car and install them on yours including the steering box.
It would probably have a bbp 7 1/4'' rear end in it too.