Given the ratio that's in it, and that it's a Posi, I'm thinking it might be a Spicer, which was used in GMCs. Some late '60s and early '70s Chevrolets with the 396/402 also used Spicers with that ratio. I guess what I mean is not so much that it might not be a stock rear for a Suburban, but more that it might not be a Chevrolet manufactured rear. I just feel it might be beneficial to ID it so you get the proper parts for it (seals/gaskets/bearings) should you need them.
