No, no Rack and Pinion in '68 on any Ford or other domestic, and darn few if any imports either.
The box would be "recirculating ball", and the power steering is "linkage assist", which is why there is a slave cylinder on the tie rod. Ford used that system much later than other manufacturers on certain models before switching to integrated recirculating ball power steering, and the rack and pinion much later starting with the Pinto in the early '70s and spreading to other models gradually over the years.
This site shows a pic:
http://auto.howstuffworks.com/steering3.htm
There is no call for anyone to be rude about this sort of thing.
There are kits to convert early Mustangs to rack and pinion, so it is theoretically possible someone could convert a '68 Ranchero. Thus, an inquiry would be in order, but not rudeness. Good luck in your efforts.