That Stangerssite has good info on steering boxes, but it was pointed out to me by the MustangConcoursForum guys that the chart has an error on the Model "F" HCC-AW and HCC-AX versions. The "P" and "M" designation is reversed on these adjacent lines. They should be:
HCC-AW 16:1 P (Power steering)
HCC-AX 16:1 M (Manual Steering, Handling Package, GT, Shelby)
It's mostly about semantics because the two boxes are actually identical and differ only in their respective preload specification and the ID tag. The difference is important to some of the Concours guys in order to get the right tag on their steering box.