That's a real oil pressure sending unit, same size as Ford's real oil pressure sending units. The one on your car originally is a fake, it only switches on and off. Ford placed a resister in the circuit going to the gauge so that full on from the fake unit reads like a nice pressure on your gauge. You can use a real sender (if it fits) and remove the inline resister from the wire harness to convert your gauge to real time. If you go back to the parts store and tell them you need one for an idiot guage you will get the original style sender. 15 psi will turn the idiot sender on and your gauge would read the ma in normal until it dropped below 15 for enough time to outlast the buffer in the idiot gauge. If you use the real sender you must remove the resister to get a correct gauge reading. There's an ariticle covering the mod in the FAQ of this site or TBSCEC FAQ, or maybe both if you decide to go with the real sender.
Don't tell me about how your gauge moves a little from time to time, it's only the small change in resistance as the contacts in the switch get pushed back and forth. Trust me your original sender and guage are just a yes or no for pressure.
Vernon