Rear shackle lift limits

Hi

Since i installed my T-18A, I had to put some angled pad on the axle to rotate the pinion. That dropped the actual height of my jeep. Now I broke one shackle on the rear last weekend, so I will do some longer shackle. What is the actual limit of this ? I think it will be around 4 inch long, is that too much ?

Thanks

 

four inches long seems pretty conservative. That is if your talking 4" total, not 4" from hole to hole. I had some that were like 6" hole to hole and that is way too much. But... always a but... if you are already shimming the axle up, I am guessing a typical 2* shim or so, and you put longer shackles in back, you will get beyond the working offset of the U joints. They want the joints to be within 3* of each other to not vibrate.