68 Dana 60 ring and pinion interchange?

What are the specifics I need to know to find a ring and pinion for a 68 b body Dana 60? Was originally a 3.54 great ratio. Still has powr lok carrier unit in it. I would like to put the correct 3.54 ring and pinion back in it. There are so many different choices, I would like to know what I need, in order to find the right set that will drop in and work.

Call DTm in Michigan. Order a full rebuild kit made by Spicer only! It will provide, shims, seals, Bears and break in additive plus proper gear oil. Then order a new set of Steels and new clutch pads. Use Dana only parts.