The quadrants for the standard, pro, and pro plus don't interchange... Adding an additional spring isn't hard to do to your existing quadrant though... a little fab work and a bit of welding to add a bracket to the quadrant and one on the mold board is all you need..schuitb;460426 said:My idea is to get a new quadrant for a pro plus or other plow that has three spring mounts.... I haven't checked on the sizes yet though.