I have a 71 SS Chevelle 454 with a factory tach. The tach is not working and I can not find a wiring diagram that includes optional equipment. Can anyone tell me what color the tach wire is in the engine compartment and also what wire is for the tach on the printed circuit board located behind the gauges. I was also wondering if I could bypass the printed circuit and wire directly from the tach to the distributor. Any help or suggestions would be greatly appreciated.