I have been having the same issue on my motor since it was refreshed last fall. After hitting every line, fitting I could find, oil filter & pan. Then doing it on the other. That motor was actually cooler at all the same places than on non refreshed motor. Swapped sending unit as well. Just left it that it had to be the gauge.

I battled the same issue for an entire season. It turned out the sending unit was t the right match for the gauge. Gaffrig gauges use a different ohm setting. My gauge read twice the actual temp.

Put some small pieces of dark masking tape in the areas you plan to take readings with the infrared thermometer gun. If the surface is reflective the gun will tend to read low.

Heck, I was going to tell him to set up (2) VAV's with chillers upstream... (worse joke)

I'm wondering if gauges are coordinated with senders? As in matched set, specially staggered so you can pass on the outside in turn 4....

new senders matched to gauges, and then a complete new gauge and thermocouple style sender.
Canton thought it was a long shot but if the pan is overfilled the oil will pick up heat from the crank. aid a lot of circle track guys have that issue due to running shallow pans.
He thought try a half a quart less oil , or move sender to different location as the oil pan can become a heat sink with no air moving across it.

I would think oil pressure would sacrifice a bit being its that much more hotter than the other oil ? Oil pressures the same as oil in other engine . I would think oil pressure would show a heat issue. And yes 265 oil is frilled hot to the touch , I wouldn't want to stick my hand in boiling water.

Have run into that putting 'air pans' under the engine compartment for aerodynamics on circle track cars, but the reason the oil temp gauge went up was because the oil temps went up. They ran about 50*F hotter...got rid of the 'air pans.' Doh !

These cars did not have oil coolers and where not to get oil coolers.

be sure you do not have a lean condition heating up the pistons

Isn't the oil in pan "hot oil" ? So after a 50 or so degree drop its 210-215? Or am I wrong?

i was thinking the same thing.hot oil from pan through pump then through cooler then back into oil galley,s.250 in the pan might be 210 after the cooler.are the temp readings the same on both engines?