I can help here as I'm doing this right now.
the 14bsf came in two widths...the 4x4 model is the one that will fit under your truck...the 2x4 is a few inches narrower. I highly recommend you rebuild this right (invest a little $$) and also choose a selectable locker (ARB, E-Eaton) or limited slip (Truc Trac).
After tons of research, I chose the Tru Trac. If this thing will see dd duties, I highly recommend the Tru Trac (to lock up both tires, simply apply light brake pressure) b/c an auto locker IMHO is not right for a dd.
When rebuilding, I HIGHLY recommend a Timken Overhaul Kit. Check out "
Complete Off Road" on Pirate4x4.com. Call them and speak with Andy b/c he will give you prices noone else can touch.
Also, make sure to match the gears in your rear to what you have in your transfer case. The code for your transfer case is in the glovebox...you will see a bunch of letters and numbers on a white sticker (now decode)
Here is a list of what you will need:
YKGM9.5-A: Yukon Master Overhaul kit for '79-'97 GM 9.5"
YGGM9.5-373 Yukon R&P (this the premium with 373 gears)
TT914A538 TrueTrac GM9.5 33 spline
Redline 75W90 (x3
YSPCS-016 GM9.5 Crush Sleeve
YSPPN-018 GM9.5 Pinion Nut
YSPPN-033 GM9.5 Pinion Nut Washer
To complete, you will need a U joint conversion. The 14bsf will have 1350, but you will need to see what is on your drive shaft and then buy the conversion u-joint. Also, if you can find the driveshaft that came with that new rear and it's straight, now you have a hd drive shaft too
For the rear disc conversion, i recommend messaging GUBNI on Pirate4x4. You can get the rear conversion with parking brake for a few bucks over $500. W/o parking brake is around $300.