Tyler,
Add-A-Leafs will add some lift PROVIDED your leaf pack is in good condition. If your springs are shot, there isn't much one leaf can do to return the entire pack's free arch to original condition. I believe if you look at the fine print, you will discover that the manufacturer says this. Adding shackles will provide lift without having to mess with the leaf springs (as Blee stated). But, any engineer will tell you that shackles add instability and are only a 'temporary' solution. That is, if you install shackles but your leaves continue to sag, you'll lose the lift you gained by using longer shackles. What you want to do is restore or increase the free arch of the leaf pack. Since your springs sound like they're shot, AALs are only going to be a band-aid. They'll provide lift but at the expense of making the leaf pack stiff and therefore ride harshly. I did a little homework and discovered that swapping F150 leaf springs for my stock leaves added about 1.75" of lift to a truck with 77K miles on it (see my 'sticky' thread at the top of this Forum). You could also purchase leaf packs with lift built in from Eaton Detroit, OME or Dever. They can be expensive, though.
Good Luck, Dave.
