What gears do you have now?...
Just keep in mind a well worn 33in tire and 3.42s will give you about the same rpm as the 3.73s and new tires
I'd think 3.42s
Heres a rpm calculator
http://www.csgnetwork.com/multirpmcalc.html
3.42 gears..33in tires...1:1 final in trans ...65mph. =2263 rpm
3.73 gears..33 in tires...1:1 final in trans...65mph. =2469 rpm