I'm assuming you have a Duster by your user name. The B body rear will work fine. Some guys will tell you to pull the springs out a half inch on each side and bolt it up. This will work, but I don't like the geometry.
Where did you get 47.3 on the perches? It should be 44 from center to center. A body is 43. I moved my perches in 1/2 in on each side and shortened and balanced the driveshaft. I'm running stock Rallye wheels.
Here is a pic, it's in a Dart Sport.
