What is the biggest lift and tires I can get with stock 15"x7.5" rims on a 1994 f150 4x4 without changing the rear gears and stuff?

 

im simply quoting things ive read in petersons 4 Wheel..but this is there advise...you shouldnt get tires that are more than 4 inches wider than the width of the rim.(obvioulsy people dont always do that..but thats what ive read)..and as far as gearing..ive heard that if its over 2 inchesin diameter (you tires)..than stock..you should get regearing..to keep your power balance where it should be..and keep everything else in line..i too have a 94 f-150..right now i have 3.08's and run 31-10.5..and its a little much to get them moving...my plan is this..to get a 4 inch lift..and get 34-10.5 under there..that skinnyness of the tire..will help get another inch of heighth..theres a math equation to see the type of gearing to do.. (new tire diameter)divided by(old tire diameter) multiplied by(old gear ratio)= new gear ratio..so for me so 34/29x3.08=3.61 so i obviouly would want to go with something like 3.73's..or something..anyway..hope that helps out