I need to do a REAL lift on the rear of my XJ

I can just FEEL those leafs twisting when I stomp on the gas pedal (350v8)
right now I have 2" lift shackles, 2.5" block and extra leaves in the stock pack for about 8" lift
I'm wondering if there is a cheaper but not shitty way to replace the stock leaves without buying NEW 6" lift leaves(keeping the 2" shackles)
Can i use Dakota leafs? or fullsize chev leaves or something else? or would I be better off getting NEW 6" lift leaf packs?
thanks