Your stock keys are mounted in your torsion bar crossmember. The torsion bars are your springs for the front end, by "cranking" these keys your just tightening the adjustment bolts a couple turns. This will then turn the torsion bars that are connected to your lower control arms and increase the control arm angle. Overall this lifts your front end anywhere from an inch to two but i wouldn't go any higher because your going to start wearing your front susp. components. The rcx 3" kit is doing the same thing but it drops down your differential like an inch or two so your really dont benefit too much from that kit. I probably made this sound alot more confusing then it really is, but if you crawl underneath your truck and find the torsion bars (about 4 feet in length and one inch in diameter bars running parallel) you will have a better understanding.