Never seen one of these before. It's on my '74 SB. Stock 1600 DP with an Auto-Stick. Number one spark plug wire has a small black rubber ring around the wire, about 4 inches up from the distributor cap. Out of the rubber ring runs a wire to the wire harness, disappearing through the firewall towards the front of the car. Looks like a connection for a tachometer, but the car has never had one. Worse yet, I can't figure how to remove it from the spark plug wire so that I can put on a new set of spark plug wires. There seems to be no way of 'un-hooking' it. Anybody know what this thing is, what it's purpose is, whether I need to continue to use it when installing a new set of plug wires, and especially how to get it off the wire to reinstall it on the new one? Any help would be greatly appreciated.
-Rich