Nope, there are really no readily available choices on faster rear axle gears for your truck.
Chances are you have the stock 4.57:1 R&P.
If you search you can find some 4.11 gears from a slightly later model axle, someone will be along with the details shortly.
Then theoretically there are some 3.90 or so gears out there to fit your axle, but I have talked to many people who have been actively searching for these elusive gears, and not one of them have found any.
The simple solution is probably an OD transmission and or a later model rear axle.
This site will be a big help with figuring gears and speed:
http://www.onlineconversion.com/bigger_tires.htmGrigg