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Put a tee there so you can keep your idiot light or factory gauge. On newer engines you almost have to use a tee because the computer monitors oil pressure and if the sender is disconnected you get a check engine light.
One more note since I wrestled in removing mine last week. . . Its very tight to get in there, takes 9/16" like beartracks posted. It look like a tiny tea cup upside down, you'll see the wire lead.
Grabbing it around the outside with large pliers and turning will not loosen the threads holding it onto the block. Make sure you start the job with a short wrench (or don't bother).