Air Lift bags (if available). They work great on my work truck. Havent let me down since I put them on four years ago. I pull a ten yard dump trailier with it and an atv/landscaping type one also.
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99 sport. rust bucket, DD, 3 car seats 04 wj (w/3 car seats too) DD duty for the lady
rubicon express lift kit with new leafs.... my only suggestion besides the air bags (a little version of what tractor trailers use)
A ZJ does not have leafs, they are coils front and rear.
I'd go with a set of HD coil springs. Old Man Emu (OME) makes a Heavy Duty (HD) coil for the ZJ that is a 2" lift coil. Being that you already have the V8 you have the factory "upcountry" coils, so you'd see very little lift (no more than 1") with going to these coils. They actually claim .75" lift on the V8 model Grand Cherokee ZJ's.
OME part number is OME943 and they have a spring rate of 220lbs.
We are happy to help if you so desire to go this route as this is a normally stocked item.