Jake,
I recently did a PS conversion on a 65 C-20. It was a fairly straight forward conversion. I got the steering box, bracket, & hoses from ABS in Orange, CA. You can use a rag joint or borgeson joint, either way the existing column needs to be cut. The instructions say to cut the shaft about 6" above the joint. I used a rag joint with a sleeve welded between the upper shaft and the shortened lower section. You only have to cut about an inch out of the shaft. It is not necessary to remove the column or the center shaft for the conversion.
Fred
