What springs were you replacing? If they were stock odd are they were sagging hard. The lift is meant to be over stock. So a flatter spring before = more lift later.
As far as the shackle, I am not sure. Are you sure the springs are correct?
What springs are they?
1985 CJ 7 258 bored/Cammed, MotorCraft Carb, Mallory Ignition, NP435/Dana 300, 4.5 RE Ex, 1.25 JKS Body Lift, Detriot AMC 20 Rear(detroit locker and Warn Hub Conversion), Herculined Tub, Chevy Heater Blower, 34" Swampers, Custom Rear Bumper, more to come....
1972 K5 8" lift, 36" swampers, lockers, custom paint.