Shackles were a popular trick to raise the rear years back; but not a great approach for stability/safety. I machined shackles for my '63 Fury last year to raise the rear 2-inches and then dropped the T-bars about an inch to obtain the desired "rake". It's actually just a bit more rake than I'd like so may re-do the shacks to 1.5-inches. I had installed HD leaf springs to bump the butt up some; though didn't get me to the rake desired. Options are to have air shocks that I had for a while then decided to dump those as the car rode like a brick. There are better and not so much ways to set the car right I've found. Depends how picky one is on this; but even the slight raise with the shackles I have exposes the leafs to "view" that I don't prefer. Who knows may dump the shackles putting the originals back on.