Todd Grisko (AKA River Beast)designed this kit several years ago. It is a well thought out and tested selection of components that allow you to flip the rear shackle of your FSJ to match a front SOA and yet maintain proper axle positioning and pinion angle.
The brackets, hardware and instructions.
RB Rear Shackle Flip Pictures
What is the purpose of the two holes in the top of the rear hanger?
Many customers have chosed to use longer 63" 2WD GM rear springs to increase articulation, provide a longer wheelbase and decrease rear departure angle. The circled hole is for the stock spring location. By switching the rear hangers from left to right and using the additional hole provided the hangers will accommodate the longer springs with very little guess work.
Please note the above modification using the longer GM springs will move the rear axle back between four and six inches and will require fender triming/modifications.
