Get a set of 720 or D21 leafs, mix and match until you find a good combination for stiffness and ride height!
Or you can get a truck add-a-leaf kit ... can raise your goon 2 inches!
This is what I did to mine! Except I flipped the kit for more low.
I disassembled the leaf pack (using big C-clamps!) used WD-40 and a wire brush to clean the majority of the rust off of them(for more smooth!) and reassembled them with some brake caliper grease (mix of molybdenum and other stuff). I clamped them all together using a screwdriver to center them, then put a new center bolt in and tightened it down ... dropped in and then added the leaf clamps for more stiff.
My setup, I used the 510 wagon main leaf, 720 2nd leaf as 2nd leaf, 720 3rd(flat) leaf as 3rd leaf, then the wagon 3rd leaf under it. I put a truck add-a-leaf flipped on the top of the pack to flatten out the leafs.
If you put the add-a-leaf kit below the setup it will be 4" higher than mine.(thats the first setup I tried)