My dad owns a '73 Ford F-100 4x4. It belonged to his dad, and lived much of its life in rural Montana. It's beat-up, but there are a few good hard parts on this truck not to mention sentimental value. The '73 steering box died, and a stock replacement could not be found after a long search. The solution was to adapt a '79 F-150 steering box to the '73 steering system. The '73 box is on the left, and the '79 box is on the right (of the driver side framerail). Note that the pitman arms face opposite each other, and that the mounting bolt patterns are not the same.