Burgie,
I just returned from the shop where I had a look at my 1970's Motors Manual. Granted this is a CAR edition, and not the truck, and not of '64 vintage as is your rig..BUTTTT, the steering boxes pictured certainly aren't the ones I described working on. The ones shown in
the book are called recirculating ball-worm and
nut type. While utilizing the same worm/sector principle, they use a series of balls captured in a ball nut to actuate the sector. Doesn't look anymore complicated, just different. Maybe a picture would be worth at million words!
Stuart.