I have a Lares 1276 manual steering box for my 67, and need a pitman arm. The box is a 16-1 fast ratio. I have read the stickys, and don't seem to get witch one is correct for this application. Did the factory switch the gearing in the steering box, or just the length of the pitman arm? I have seen two different lengths mentioned, but no mention of the box ratios they are used on.