Get the front brake lines from the master cylinder down to the proportioning valve and the prop valve too. When you get all of the lines, you can bolt them to the early truck as a unit and have nice factory bent stuff. Personally, I'd buy new front brake hoses. I don't like to reuse something like that. They're made of rubber and they do deteriorate over the years.
Use the later master cylinder, all the lines, and hoses. The later model proportioning valve will mount to the front crossmember perfectly. I've done this on trucks from 63 all the way through 72 model. Here's a 63 I built last year. Every single brake line, hose, and master cylinder was from an 80 model truck I parted out.
