I've found the 3rd generation Camaro diffs at 62" from wheel mounting surface to wheel mounting surface work well in the AD truck and should be applicable to the later models. These diffs are most commonly found in a 3.08 and 3.42 R&P ratio. The 3.73 ratio was also available but not as common as the 3.42 from behind the 2.8L V6 in the automatic cars.
Being a coil spring diff you'll need to burn/grind off a bunch of the mounting brackets and weld on your leaf spring perches. The Camaro emergency brake cables can be slightly modified (turn-buckle & cable clamps) to tie in with the stock truck emergency cables. In addition, the Camaro rear sway bar can be flipped from the bottom of the diff to the top, using only the Camaro hardware, and will bolt up to the frame requiring only 2 holes to be drilled. If by chance you're running a T5 transmission the S10 short bed driveshaft can be bolted in without shortening or modifying the U-joints. I've used both the drum brake setup from an 88 and also a posi/disc from an 89 IROC-Z. The "Z" diff has some drawbacks as axle seals for these Australian Borg Warner units are almost impossible to obtain.
The advantages of using the Camaro diff are that they are 5 on 4-3/4 bolt pattern, the correct width to center the wheels in the wheel wells, most times lower mileage, with swaybar/emergency brakes adaptable and the best part is that they normally sell for $100-150.00.
The only negative I've found is that you'll need 3-1/2 to 4" backspacing on a 15X7 or 8" rim and if you're running a disc conversion on the front, that backspacing will clear both the stock and upgraded tie rod ends with 235/70/15 tires. Not many salvage yard rims available in that combination.
Dave
