That my friend, is your knock sensor. You have to drill and tap the 3.0 block and reuse the 2.5 knock sensor. The 3.0 version has female connector, the 2.5 has male (or vice versa, I actually forget which, but I know it just ain't the same).
The 2.5 sensor is the "nipple and threads on the cap" type. The 3.0 has a hole in the sensor that a screw is run through into those (smaller) threads. I actually bought and returned the 3.0 version.
Good luck! Do me a favor, let me know if your oil pickup tube fits on the 3.0. Mine didn't (until its bracket was bent to fit), but I have not been able to find anyone with the same problem. It's been bugging me ever since why I am the only one with that problem.
