Try bias 36's, a clapped out 4.0L with 350K on it, and 3.73s and a 5spd...
It was 4-lo or don't even bother trying to drive it down hill
5.13's get my vote.
Haha, I was about to post that I have been running 35's, 3.73's, a 2.8l, and a 4 speed, but I think yours takes the cake.
To the original poster, I would definitely go with 5.13's, especially since you have overdrive! Choosing the proper gear has to do with more than just tire size and RPM's. You really need to take into account how much power you are making and where you are making it at.
To the guy who said that 1500-2000 rpm at 65 mph was optimal, that is all fine and dandy if you have the torque to keep the truck moving. As I said, my Bronco is currently running 3.73 and 35's with no overdrive. Now I calculated my rpm's at 70 mph to be about 2400 once, which should be at or a little above this "optimal" range at 65 mph. Now, given my truck only has a 2.9L, I absolutely hate this gearing! It is definitely geared way too high, and squanders what little power my engine has to begin with. The slightest mole hill will cause me to lose speed! So, as I said earlier, you power output has a lot to do with what gear ratio you should choose.
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