[67C10Step]

Can't help much but with the speedo bouncing. After driving mine a bit it was bugging me and figuring the cable and cable housing had never been cleaned in 55 years I decided when I was installing the new speedo gear to disconnect the cable at the speedometer as well. Cleaned the cable housing by repeatedly spraying carb cleaner down it and then blowing it out with compressed air. Once that was mostly clean I took a shop rag, sprayed it with carb cleaner and then wiped the cable until it was pretty clean as well. Greased it all up with Lucas grease and reinstalled. After the first drive it runs smooth now.