My 68 convertible's original speedo worked well but the odometer did not. I bought a used speedometer (just the gauge). I removed the instrument panel (speedo & fuel gauge). Seemed pretty easy (except the ground was screwy the first time I put it back together so I had to do things twice).
I took it for a quick drive. Odometer worked but speedo was jumping all over the place and was making "whiz" sound from behind dash. Is it possible to hook the cable up incorrectly at the gauge? I didn't have time to take things apart again but hooking the cable to the back of the speedo was the easiest part of the whole swap.
