question about instrument cluster

If your voltage limiter went bad, fuel, temp and oil would all be affected. The tach is on a completely different circuit and is not fed voltage through the limiter. I would check and clean the bulkhead and sender connectors.

http://www.mymopar.com/downloads/1969/69BarracudaA.jpg
http://www.mymopar.com/downloads/1969/69BarracudaB.jpg