limited slip rear for 87 truck/91 suburban - donor vehicles and ratios?

[Chuck78]

My daily driver is an 89 suburban (fyi through 1991 suburbans are the old body style like 73-87 trucks). Just got a bunch of 89 suburban parts in the junkyard to bolt to my 1962 GMC 1000 panel truck. I figured since I am going to have the entire front crossmember/suspension/brakes/steering/steering box/ps pump/booster & MC/etc off of an 89 suburban, I might as well be looking for an 89 suburban rear end as well, so that it would make future parts sourcing easier. The 63-ish and older rears are a weaker 12 spline I am told(newer are a 30 spline), and all the pre-71-ish are the harder to find 6 lug pattern. Since I'd have to buy special custom 6 lug aftermarket rotors in front for the 89 front end on the 62, and I already have back wheel spacing issues that need resolved, I might as well just do the rear end now and get a newer 5 lug axle...

Anyhow, I wondered how common limited slip rears were in these years of trucks? I have a coil rear, but coil suspension truck differentials are few and far between, so my sources are limited (1990's Caprices??? have the 5 on 5 bolt pattern). There are kits to convert any leaf rear to coils, made with my era of trucks in mind. I might just look for a Caprice 3.08-3.42-ish posi, maybe a 3.73, and just swap on suburban rear brakes if I can. Swapping the whole suburban rear is not out of the question though, hence the post.

Thanks!

Chuck