The fuel sender is compatible with the Autometers, Shelby guages (made by Autometer) and the Smiths if you have a guage in the 33-240 ohm range. As Tom says they don't work all that well as the sender tube has been bent for a front entry into the tank which doesn't make much sense to me as a tank builder. The sender is a nice set up and needs calibrating per
http://www.centroidproducts.com/3wire.htm I prefer the two wire as they eliminate the need for a hot wire running the length of the car. Basically if you pull the sender out and empty it of fluid, hook it to your guage (ignition on) and set the empty level screw. Submerse the tube in a can of gas and set the full screw. Reinstall it and don't trust it under 1/2 tank...........