this guy used the stuff from a '83 suburban in his 1966 c20:
http://www.persh.org/pickup/pickup-beginning.htm He has several articles on how he did some of it.
He even used the REZ kit that 64Fleetside mentioned:
http://www.persh.org/pickup/steering.htm Check it out.
Here is a tech article from one of the truck magazines, using the same kit:
Tech Articles
Power Steering Retrofit - Make Your Classic Truck More Driveable
Adding Power Steering
By Bob Carpenter
http://www.customclassictrucks.com/techarticles/60_66_chevy_gmc_power_steering_retrofit/ enjoy,
-W
several vendors sell the kit from REZ, but this is their information:
REZ Engineering - No website yet, call or write - power steering kit.
used trucks to part out(particularly 4x4).
1960 - 1966 Chevy/GMC. -
PO Box 1584 - Great Falls, Montana 59405
Ph. 406-727-9267