Aftermarked Rack and Pinion Square body

i have seen alot of people that doing custom c10s add Rack and Pinion to them insted of the old sloppy steering
im thinking why not do the same to a C30 ? has it been done? does it need to be speciel Rack and Pinion unit or can i go to the local junkyard and get one from a high end saloon car?

These should help.