Shackle angle - BOR leafs?

I currently have a 4 inch S-10 bastard pack with stock shackle and stock box. I was planning on modding the shackle box to get a hair more lift and improve the stock shackle angle.

Now, I also plan on getting the Big Offroad 4 inch packs later on. I understand these are longer than stock. Does anyone know hoe much longer these are so I can build the options into the shackle box when I modify them? Thanks!

PM yellaheep. He can answer all the questions about the BOR leafs.

I will, thanks Lt. (I'm a FF in Oregon).