ok i have a 4 inch drop in rear. Shackles and hangers. Is there a shackle i can get that can drop the back another 1 inch??

tony

 

One way is put new main leaves in with re-arching or the eyes adjusted for the extra drop.
I would not use the longer shakles if stabiity means anything.
Have you checked shock travel with the lowered trim height? May need shorter shocks now.