There is a conversion for the older power assist steering that uses the original box.

http://www.thehollisterroadcompany.com/media/1947_3800/47truckassembly%20008.JPG

Its not a cheap setup but adding power steering isn't cheap.
I think I did this one for about $500. Uses a GM pump and early Chevy power assist parts. 67 Chevy truck is what i used and made the drag link. Corvette up to 81 or 82 used this type of P/S



Dave Chapman
The Hollister Road Company
713-937-0387
[email protected]
www.hollisterroad.com
www.thoroco.com