GM trucks up to and including 1967 (and certain 1968's) with power steering did not use the Saginaw integral power steering box as you have on your truck. These trucks used the hydraulic ram type steering assist similar to a '64 and older Chevy Impala or many early Corvettes. The actual steering box, shaft (with 1 rag joint at the box), and column are the same if the truck has power steering or not. The hydraulic cylinder attaches to the frame on the left side, the other end has a ball joint that attaches to the center link. The center link has a control valve on the end where the pitman arm connects. Good pictures here of what it's supposed to look like:
http://67-72chevytrucks.com/vboard/s...d.php?t=253657