[PGSigns]

Parallel is both bars at the same angle. It will allow the rear to move well with truck. A ladder bar is not a good choice for the street. They don't allow the rear to roll much. So when you pull into a driveway and you have the angle change with one tire going up first the four link will articulate well and the ladder bar will move till it binds. I have seen street driven ladder bar cars break the front mounts off the frame and crack the axle tubes. Google parallel four link and you will find lots of info and pics for running like this on the street.
Jimmy