I checked Randy's Ring and Pinion and you are right. My Dana 70 has 4.11 gears in it and it looks reasonable to change it to something my fuel budget might like better. It might move under a truck afterall. Its been sitting out back for a couple of years.
Looking through that site it should be easy once someone has identified a rear to get a good indea what the options are, or at least what is available today.
