The simple answer is that it replaces the stock sender. It is uner the distributor and has 1 wire on it. The easiest way to wire it is to run a wire from the sender directly to the gauge. DO NOT try to use the Autometer sender for the stock gauge and the new one. They are not the same and you won't need the cluster gauge anymore anyway <G>. That is what I did. DO NOT cut the stock wiring-just tiewrap it out of the way-no harm. You can get power from any switched source on the dash fuse box.