I' just finishing the rear up on my 88 Xj witht he Rock ready leaf pack and lift shackles to a totla of 10+ inches. I know I need a new rear shaft or cut it down. The pirches come with shims that roll the diff up to reduce the angle any clue where I can find a new shaft for cheap. I got a bud who is awesome with metal, welding, and cutting. How do I know how much to cut? Can I just buy a new one at the right length?