It should all swap over except the driveshaft. Why not fix the Duster? If it's a genuine 340 car, it would be worth more. (and looks better in my opinion)
I do plan on fixing up the duster. But my Dart is my first real muscle car and I have grown really attached to it and want to finish it first. The duster i plan on going panther pink so me and my wife can cruise together and she feels cool in a pink car. Even i have a soft spot for the panther pink cars.