Q: Which thread do I need for my Ranger/BT50?
A: This is in reference to the thread size used on the rack side of the steering rack end. Based on our experience, you can not know this merely from your year/spec, as we have found no correlation. Ford seemingly grabbed random racks of the shelf when building the Rangers and BT50. So the only exact way to tell is to slide the steering rack boot back and measure.
Generally if the rack end joint is bigger than 37.2mm, you have a M16 rack. If its smaller than 37.2mm you have a M14 rack.