A 6 volt gas tank sender works in a range from 0-30 ohms. A 12-volt sender works in a range from 30-90 ohms. The sender has to match the gauge you are using in the dash so if you still have the original 6 volt dash gauge you will need a 6 volt sender. I have had the best luck sending the original senders off to get rebuilt. Then you know what you get back will work and will fit. If you figure the first one lasted forty plus years the rebuilt one is good for the rest of the time many of us will spend in the garage....
Randy
