post your stock gears,look on your rear axle there should be an aluminum tag on the bolts that have your ratio stamped on it,example it will read 3:73 or 4:11
also while your down there look at your oil fill plug on the rear diff cover let us know if its a plastic plug or a metal plug with a square hole in the center.
4 or 6 cylinder,auto or manual?
give as much info as possible to help us help you.
with that said I have seen a 4" lift run 35's but full flex will eat your fender flares.
a 4" suspension with a 1" bodylift will work
also what kinda lift do you have,suspension?body? or both?