Low oil pressure makes me nervous

R Ehrenburg DOES have some history with Mopars.... interesting that the old senders had what is called 'hysteresis'. Do you have another gauge yet? I ask because your present sender can be OK but the gauge off, and the new sender would not show you that. You need a 100% independent system for a valid comparison.

And BTW, if your instrument voltage regulator (IVR) in the dash is ****'d, then it will throw off ANY sender/gauge combination.

Since you have found a table of sender resistances versus oil pressure, you can just connect a long wire to the sender, run it into the engine compartment, and use an accurate ohmmeter to record the sender resistances as you drive. Then you can reverse translate to the actual pressures you had. That takes any gauge error and IVR problems out of the readings. I do that in checking the Mopar temp sensor systems, which work in the same way (variable resistance in the temp sensor controlling a thermal gauge movement).