52 3/4 ton rear options

[f18delta]

I finally got some cash in and can afford to buy something used

Need to know my options for a 3/4 ton rear end. As it sits now, I have the frame sitting on the original axle. The leaves are shot, I'd like to change out the gearing since it's original as well, and I have some air shocks that I can put on it. If possible, I'd like to move to 5 lug wheels as well since I'm going to get a Mustang or equivalent front end later.

Anybody have suggestions of what I could pull out of a newer model that is:

1. A direct fit
2. Geared in the mid to high 3's
3. Has or can be converted to 5 lug (drum or disc, doesn't matter)
4. Won't take all my cash to buy it and get it installed

I'd like to spend less than $1k on the entire rear set up. I'm pretty certain this can be done, but when I checked prices versus last years, I'm beginning to wonder.