PS Gear Box Rebuild

Which center link will you be using - 72 and back or 73 and up? Or to put it another way, try to use all the parts from similar years in the rest of the steering linkage. 72 and back mount the pitman and idler with the tapered stud in one orientation - pointing up; 73 and up uses the opposite orientation - pointing down. The 73 box will therefore have a pitman arm taper pointing down.