I make my wish bone so it is level at ride height. In the middle of the frame. Now on drag cars they can be pretty narrow because of the tires on a truck I try to make them as wide a possible. If you look at this picture you will see how I mounted it to the frame the single end mounts to the top of the rear. If I'm doing bags I take them out and raise the rear as high as I can measure it. Then lower it all the way and measure it.