The pitman arm on my sprint car is 14 inches long the steering arm at the spindle is 5 inches long and the drag link is 50 inches long. The drag link is no where near level and travels up hill from the pitman arm to the steering arm at the left front wheel with no ill effects. I would think a drag link of that length or the length your gonna need would have very little effect on bump steer or arc. Now if that drag link was only 15 to 20 inches long such as using the old Mustang steering box I would say you had better be sure the drag link is level. Looking at your pictures I would say your gonna need a longer pitman arm and a shorter steering arm at the spindle. you don't wanta use the steering box as a stop,do that at the spindles and please please get rid of that wrench for a steering arm (it looks Skeeery) you gotta remember if that breaks you loose all steering ability.