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.
Ok, is there an 8 1/4" rear (since those are better than the 7 1/4" but cheaper than the 8 3/4") that will drop in with NO modifications. I do NOT want to monkey around with driveshafts or anything else. It's for a stock daily driver and I just want to get it back on the road and be reliable. I don't want the car in my garage for a year as a project. I basically want to buy a good used one bring it home and put it in the same day. If there isn't then I'll just look for someone with a good cheap used 7 1/4" with 2.94 gears