1971 dart rear differential

I have a rear chuck 2881489. It is on an axle which measures 34 1/2" center of spring pads. and 49 7/8" inside backing plates. This axle is completely rebuilt and was given with parts that I received with the car (71 Dart).I'm looking for thoughts , ideas on what to do. I would like to keep the chuck and find a axle housing and axles for the dart. I don't know the ratio, however it is a sure grip.