Any GM 1971 to 1982-ish front 4x4 axle is a Dana 44 and is a direct fit with disc brakes. Mid to late 80's became the corporate 10bolt. It was used from 80's to 1991 in Blazer, Jimmy and Suburban. It will still bolt in but I think there are some small differences on the internals. You will need to address the brakes Drum/Drum to Disc/Drum is you go that route.
http://seattle.craigslist.org/see/pts/3477254441.html
http://seattle.craigslist.org/sno/ptd/3460687257.html
http://seattle.craigslist.org/kit/ptd/3461979458.html