I used to have a 71 Travelall with the same engine and cable set up. I wanted to get rid of the speed sensor, but an IH shop said it was part of the emissions set up. I'd check in your state and see if it would give you any problems clearing emissions. Bob K PHX AZ
I own a 75 & a 78 Scout both auto. They have a one piece speedo cable.Can be purchased from the Scout Connection 319-372-3272.
These guys have always been extremely helpful and have fair prices. I always call them first when I have a question.