Greetings: Could someone tell me if there are instructions available on what is required to add a factory tachometer to a car that is a non-tach car? My car is a 1968 Convertible. I purchased a restored factory gauge assembly w/ housing that has a tachometer in it and I would like to switch it out with the non-tach cluster. Any assistance / directions regarding the electrical / wiring would be greatly appreciated. Thanks..