Per Stewart Warner specs, these are 80-10 instruments. 80 ohms = no needle movement. In the case of fuel gauge, 73 ohms will lift the needle to the first/empty hash mark. The tester used by service techs had less than 80 ohms for starting point because 80 or greater ohms would not have been a test. 80 or greater leaves you scratching your head, "Does it work or not?" I hope that makes sense.