Also, when I got home today, I glanced over at the differential out of the '84 and noticed the drums were a white/silver-ish color. Thinking to myself "I wonder if those are the aluminum drums?" Sure enough, I got a magnet and it would not stick to them, but yes to the rest of the differential. I almost feel sad that the differential will be swapped for a (heavier) disk setup.

That sad feeling will disappear on the first canyon run you make!