I have a question concerning the ignition that came with my engine. This is my first gasser so pardon my ignorance.

The Ignition has 4 wires coming out of it. The wires that come from the sensor only have 3. I ordered a sensor directly from CH with 4 wires. Looks like the 4th one is a ground. Do I need to switch sensors or is the 3 wire setup ok? Hope somebody knows what I am talking about.