DONT DO IT! DONT DO IT! DONT DO IT! I hope I got your attention.... I used the new torsion keys on my 02 2500HD with shock adapters. Looked good,3" in front and a 1" block in back. I dont care who says what... your ride will be compromised severly! Your suspension(torsion bars) will be so wound up you will loose all your comfort of the suspension. As I found out after only 18 months with the keys, My upper control arms where on such a steep angle to the knuckle, the upper ball joints,lower ball joints,control arm bushings where waisted!!!! Every little bump you hit will be magnafied to the extreme. Even if you use the cognito upper arms to put a better angle for the upper ball joint it will still ride like a wwI tank!!! Also your alignment will be out for lunch and never come back. This is very important for towing and you will loose alot of caster that the truck needs to tow straight. Dont waste your money,you will only have to do more repairs sooner than later. We all know the 2500hd front ends last almost a lifetime if not messed with.