I would add one. Not familiar with those "rigs" but the A bodies are "famous" for poor grounding, which originally was through the cluster mounting screws. Just add a piece of wire and bolt it to the dash frame or column mount
Could you run a wire to the negative on the amp gauge to the dash frame to ground the cluster better? Would i would like to ground mine better but I don't see anywhere to put a ground in the cluster. Other than the negative side of the amp gauge
