By contrast, when resistance to ground at the sender is high and current flow is low, the gauge will read low. Sending units, be they temperature, oil pressure, or fuel level, are all variable ...

Check out the 1949 Chevrolet 5 in 1 Gauge Cluster by Haneline USA, and the adapter ring that fits the 49 Chevy with a Speedometer, Water Temperature, Oil Pressure, and Fuel Gauges - Rod & Custom ...