the 7700 package has a stiffer spring rate, to accommodate the additional payload capacity. You have stiffer springs, but the same (approximate) sprung weight as a standard f-150, therefor you have less sag on the rear end, and it sits higher. The spring rate is determined by a couple things, one is the number of leaves, the amount of arch (as ya'll covered a couple pages ago), and the thickness of the leaves. The other things the 7700 package came with are the 4r100 which is nothing but a tweaked and renamed E4OD in use on the heavy trucks since 88, a semi floating version of the 10.25" rear end used in the F-250 and F-350 trucks, and the strange 7 lug wheels Ford thought were a great idea. I believe the front spring rates are a little higher as well. Basically it was Ford's take on an old GM idea, from 87 up GM made a whole bunch of light duty 2500s with 6 lug semi float axles and a whole bunch of 1500s with 8 lug semi float axles.
now thats the answer i was looking for thank you sir! i know what else comes on the 7700 as far as gearing, thicker torsion bars, 4r100 tranny, rear end and i think there is a couple other odds and ends if im not mistaken. just wasnt to sure about the springs, i knew it sat up higher but wasnt sure if it was because of spring count, which we found is not the case, or that they are arched differently or stiffer. glad i asked the question. now we all know the differences! thanks again dude!
