We've gotten a bit off topic here. buzzindozens truck is a C20 3/4 ton, so none of the 1/2 ton stuff will work. Just from my quick research on the most likely rearends that would be used for a swap, the GM 14 bolt, the Spicer 60, and the Spicer 70, it looks like 3.73 is the common gear. There are listing for a 3.42 in the 14 bolt, and a 3.54 in both the 60 and the 70. I do know that the 60 is pretty common in the 3.54 gear, usually in Dodge or ford van applications.
