So I have a lowering shackle in the rear of my 1992 C1500 to make the truck sit level. However I am adding a 4" lift kit including lift spindles and a 4" rear lift block. Will this work fine with the lowering shackle? Or should I get a 2 inch block, and go back to a stock rear shackle? Has anyone done this before? I just worry about vibrations and whatnot...thanks!