depends on what your rig is going to end with. I ran two sammys with 31's over the years and 1.3 was just fine, I also daily drove it 100 miles round trip. I added 4.62 diff gears, and a weber, KN-airfilter system. I on 31x10.5's could pull 75-80 on hills, wind, highway no problem.
So it all depends on what your going to do to your rig, no gears? then a 1.6