I built a Samurai with 5.38s and a 4:1 t-case set with 35" tires and it was
way underpowered in low range but that was behind a 1.3 engine too.
I think you will want the 6:1 t-case set and 5.29 in the diffs to turn that
tall of a tire on the street.
I don't think there is any way you could run the Sidekick case in low range
and then run that through a samurai case and get any sort of highway speed
My sidekick stock in low range would go about 55 at 5000 RPM on 235 tires,
taller tires and gears might help, but I don't think you want to swap in 3.73
samurai gears to get any sort of speed for highway use, but run the #s thru
a gear and tire calculator to figure your speeds before you build
Wild