I used a power steering box from a 1/2-ton '83 Suburban with a Rez mounting bracket on my '65 C20. The pitman arm hole was just the right for my '65 3/4-ton linkage. Since I also used the 350 engine from the Suburban I didn't have to worry about monuting a pump. All I had to do was find some hoses.
BTW, I did update the Idea Page with 3/4-ton rear cab mount information, if you care to have a look.
Cab Mounts
