[Mike C]

'91 in Suburbans and Blazers. 1987 in trucks. Somewhere around 1980 they switched from the Dana 44 to a 10 bolt Chevy in the front and from the 12 bolt to a 10 bolt in the rear. Six of one, half dozen of the other IMO.

There are some caveats for you. If you get a Dana 44 you can swap your gears into the open knuckle housing. But if you buy a 10 bolt unless you have fairly common gear ratio of a late model truck, you will need to buy new gears and have them setup.

I wouldn't waste my time on the 12 bolt discs. The drums are more than sufficient in the rear. If I was doing anything, instead of just a front swap I'd swap front and rear from a 3/4 ton truck. The semi-float 14 bolt and 10 bolt front from an early 80's through '91 Sub is a great swap that gives you significantly more powerful brakes.

I did this on my Jimmy with a factory set of 4.10 from an '86 Sub with HD towing package. We are doing it on my kids Jimmy with 3.73 axles from an '84 sub.