lower the back 3 inches

[aussiesteve]

who sells the rear lowering kit to drop 3 inches in the rear of a 1992 2x4 GMC extra cab, i dont want to change my new shocks i just bought.

 

[GoToGuy]

The shocks and the axle exist on two different planes of attachment. Any relocation of axle changes the shock stroke based on axle location. ie- lift blocks, longer. Lowering blocks, shorter. Unless you changed the lower shock mounts to lower axle saddle mounts, then axle on top of leafs. Thus the axle relocation will drop the rear without major surgery.
That's my quick thoughts. Good luck!