[deucemac]

That same gauge system was used all the way up to 1985 save 1956. Then ford, in their infinite lack of wisdom went to the magnetic gauges like GM and we had trouble ever since. The gauges have no idea what they are reading and I have often taken a much later gauge with the same sweep, changed the needle and face from the older gauge and used it without problem. Ford Torinos and Ranchero Gt's from the '70's have donated their gauges for me on several occasions. The beauty and simplicity of a King-Seely gauge is incredible. Ford made a gauge tester that would fit to the sender wire and work for both 6 and 12 volt gauges, though only designed for 12 volt.One position checks the "IVR" but since the 6 volt doesn't need this function, the 6 volt gauge will respond to the test of low, middle, and high for gauge needle position. I used mine since the early '70's when I started in Ford dealerships and have it yet today squirrelled away in retirement. I guess I am a natural born pack rat.