1968 Dart sudden rear end noise.

Oh chit, I read B-body 8.75
and immediately went to 66 Coronet.
But
To answer your question, all A-bodies from 67 to 76 or so, will have rearends that swap any which way you like, except with various proviso's like;
Driveshaft length, tube diameters, size of brakes, and where exactly the the rear flexible brake-line mounts. But
any rear will physically drop onto the springs in the right location, and then begins the hook-ups.