[Sailfish]

My Superformance came with the cable type speedometer. Initially, it bounced and jumped and was anything but useable. I installed a longer speedometer cable (to ensure there were no tight radius bends) and it became dead-on rock steady. I put over 20,000 miles on the car and had to replace the speedometer reverser twice. A real pain to remove and reinstall the speedometer, but in my mind, well worth it. To maintain it close to "period correct" was worth the repair costs and headaches with removal and reinstallation. Mark me as a cable guy.