I think I am going to swap axles with a guy in Houston. I have 4.10 open and he has 3.55 LS. I can gain 2-3 mpg with those gears. My 4th with 3.55s would be lower than my current OD, and of course my OD would be almost 15% taller. Given the fact that I don't tow huge loads and I don't tow too incredibly often I think this would be a good move for me. i'm averaging about 20,000 miles a year right now...
I just have to make sure they are in good shape. I know I have a nice leak on my right rear...