Ladder bars are sophisticated suspension linkages that connect the axle housing directly to the chassis. When using ladder bars, the engine's torque goes directly into lifting the nose of the car instead of twisting the leaf springs.
You'll need to fabricate the ladder bars, the crossmember to which the front of the ladder bars attach, brackets to weld onto the axle tubes and hold the rear of the ladder bars and a diagonal track-locator bar that connects the front of the passenger-side ladder bar to the top-rear of the driver-side bar.
You'll need to use spherical Heim at the front of the ladder bars where they attach to the chassis and at the rear points where they attach to the axle housing. Failure to do this will result in massive suspension bind and ultimately suspension failure.
Instead of threading the Heim joints directly into the ladder bars, you might consider sliding a reverse-threaded rod into the tube ends, welding it in place and connecting it to the threaded Heim joint with an adjuster nut. This will allow you to fine-tune the suspension geometry to correctly align the axle and preload the chassis.
