67 Speed Sensor

I am looking for some guidance. I am almost complete with my '67 Mustang Classic Update (wiring harness) from American Autowire. I hit a snag when trying to finish off the vehicle speed sensor. Essentially there are 3 wires coming from the new harness (VSS Power, Signal, Ground). The speed sensor coming from the transmission has 4 wires. I cant get under the car as I dont have a lift, but wanted to see if anyone can identify what i am working with here. Is it a 8000 pulse or 16000 pulse? and why 4 wires? everything is melted or chewed up. Thanks for any input.