[Flat Ernie]

Yes, it does.

They are not variable rheostats at all. They operate on the principle of differential heating. There are bi-metallic strips (a strip of metal with two different kinds of metal on each side bonded together that have different coefficients of expansion). When heated, they bend and when bent, produce a different tension required to move.

Pick up a Ford Service Bulletin - it explains the operation well.

Bottom Line: You need 6V to the gauge for it to operate properly. You can get close with a dropping resistor, but I'm of the opinion that the gauges work much, much better and far more accurately with a constant voltage regulator. The 7806 CVR produces 6V output with an input of 10-18V or thereabouts. This gives far more accurate gauge readings than even the stock 6V system because the voltage is steady and constant. You need one per gauge - although different CVR will have a higher output current and can run all three gauges - oil pressure, water temperature, and fuel gauge. These are cheap enough (<$.50/each) to run one for each gauge and keep a spare or two in the toolbox.

Your voltage gauge requires a dropping resistor of approximately 60 ohms. You need to use an accurate, precision, wire-wound resistor of exactly 60 ohms for this purpose. The el-cheapo radio shack carbon resistors are not nearly accurate enough to use for this and the precision resistor will only cost a few dollars at most. This will put your "green band" right at about 13.5-14V on your gauge.