If you were to buy a leveling kit, all they would sell you is the torsion keys. The point is to level the ride, your ass end sits higher than the front stock. Hence a basic drop is 3/5, 3" front and 5" rear to make it level. So if you added keys to bring up the front, then added spacers in the rear, you'd still have rake, and wouldn't be level. Maybe someone else will chime in and correct me if I'm wrong, but unless you crank those Ford keys a lot, I don't see you bringing the front end higher than the rear.
And how is a 2x4 you guess considered a 4x4?