I'm going to make new mounts for the front of the rear leaf springs on my 48 chevy pickup. will just shortening these drop the rear any? If not, how much if any can I shorten the rear shackles? the rears are currently 5" with quite a bit of space where I could probably take 2" out. If nothing else I will probably box the frame and just make new rear shackles that mount quite a bit higher. Thanks