Shackles take what, an hour to remove and reinstall? And they're cheap. Lift blocks may take a little longer to install, but they too are cheap. I'm all for saving money, but sometimes using what you already have is counterproductive. 4" spindles and 2" blocks are the least complicated way to achieve what the OP wants.No it doesnt.
But if someone already has the lowered shackles installed, and the stock length OE ones are long gone, AND gets a great deal on a lift, I suppose someone could just use what he has.
And ask questions about it here.
I suppose someone could also take the OE shackles from the lifted truck and eliminate the worry about the "vibrations and whatnot"