The beauty of these old style carriers is that you don't have to pull the entire rear end out to work on it. You can pull just the 3rd member and do/have the work done to it. Also, you have the 3.38:1 gears set. Great to make it freeway friendly. But, with another 3rd member, you could set up a 3.90:1 gears set and it's an easy swap to go between the two.

Same axle housing, just swap the 3rd member. Consumables are the 2 gaskets and some 90 weight.