There are a couple easy ways to test this without taking anything apart. The simplest is to find a buddy with a car trailer and load the truck on it. Then, measure the height front and rear at the fender and strap that bad boy down by the frame, NOT THE SUSPENSION. Then you can tighten the straps until the truck is "lowered" the extra inch. You can then get in it, start it up and turn the wheels and do all your clearance testing.
The second way is also using straps but you will have to figure out how to use them to compress the suspension. I've done it a lot on older trucks, but it is harder on newer ones since the inner fenders are so closed in.