I was just giving my thoughts on boiling down the year. It is for others to mull and dissect if needed. Just brainstorming and trying to reason it out. If you are going with custom cable, you don't need to know for that. When you need parts for shoes (probably 2x11) and springs and etc., they sell universal hardware kits which will cover any internal part you need. Post when ready for that stuff. Drums may have diameter of shoes stamped on them and measure width of shoe. The diff you have is nice and strong and well liked. I had a 12B panhard donor rear end in one of my trucks. Did you notice that it is a little wide? If it is a 64-65 it may be a little bastard'ish for some parts.
You will have to have the mechanism that the threaded end attaches to in order to get length measurement.

Right is right, even if everyone is against it, and wrong is wrong, even if everyone is for it. - William Penn