To be certain:
* Consult a repair manual: A Chilton's or Haynes manual specific to your 1996 F-150 and engine size will show you a diagram and the precise location.
* Use an online parts diagram: Many auto parts websites (like AutoZone, Advance Auto Parts, etc.) allow you to select your vehicle's year, make, model, and engine, and then view diagrams showing the location of parts, including the CKP sensor.
Looking at the diagrams will give you the most accurate information for your specific truck.