The radius rods have to be parallel with the ground. The shackles go on the rear spring hangers, I would say around 45 degrees to the back. Make sure that they are angled enough so that when you hit a big bump, the shackles won't go over center and end up being forward on the spring end. You will want to crank in about 5 to 7 degrees of caster with the springs compressed to ride height and the full weight on the car resting on the suspension....