A 5.5" would be very close to level. I believe that a stock F150 is 2" higher in the rear than in the front! If you lift the front 6" and the back 4" it would be level. Now if you take out your factory block and replace it with a 5.5" Pro Comp bump stop block it would be very very close to level from my thinking. The thing I like about Pro Comp is that they do have the bump stop built into the block where as the Rize is just a plain normal block. An AAL is only good IMO if you haul alot of weight or tow alot of weight. I dont like them because I dont tow very much and makes our trucks ride alot stiffer in the rear. Another option you could look at is to take out your factory block and just have 1 in there and then put on a lift shackle which will keep your ride quality.