Just to inform of my findings. To get that last inch I desired on my McGaughys rear flip kit, I was able to use their GM short shackle. This was used in conjunction with their adjustable spring hanger. This will get you back the inch you lose when you trade out your stock hanger and use theirs. I have put 180 miles on this new setup and it rides perfectly. No binding, clunking, or squeeking. The shackles clear the spring and the hanger just fine. Ride quality is great, no change from stock shackles. Others might have a problem if you still have your stock hangers equipped. These shackles are specifically designed to work paired to their adjustable hangers. All in all, if your looking for maximum drop from your flip kit, just leave your stock hangers on. Looking back, that's what I should have done. Now the truck is sitting exactly where I wanted it to be.