My tach seems to be way off(double the actual speed), and strange things with the lights happen. If I turn on lights (park or head lights) and dim the gauges, the gauges reduce the reading. Oil, water, and volts reduce while the right turn signal indicator glows dim and solid. The exterior lights work fine. Also with lights off, when I turn on right turn signal the gauges and tach jump with the blinking of the turn signal. The left turn signal works fine. This car was bought as a basket case with blown motor. It has 350 now but I am wondering what all may have been done before I bought it. I have found loose and missing bolts and nuts in dash and gauge cluster. Any ideas????

 

Any help??? Could the inst cluster be from a 4 or 6 cyl causing the tach to be that far off?