Yes, but I believe it also controls dwell time to the coil. Excessive dwell could overheat the coil? Also, using a timing light I've noticed very erratic unstable movement of the mark. I know the distributor is good, had it rebuilt.
Here are a Speedometer from a 84' Spider and a Tachometer from a 78'. Both tested and working, the black trim on the speedo is cracked but not visible with the bezel installed. Both are cable driven. $65. ea. plus $15. shipping to lower 48 only with PayPal only please. Bob Lesher in Oregon