Oil Pressure Gage and Sending Unit Revisited

There is another possible cause. You would have to pull that gauge out of the panel to see it. In the beginning, all 3 of these thermal gauges were different. Main difference was in the slot where needle is attached to bi-metal beam. There was a design flaw in the oil gauge that had to do with needle weight and gravity. My guess is Stuart Warner never tested them positioned same as they are in the car. How they corrected this? The temperature gauge design became the oil gauge too. They simply put the oil gauge screen on it, adjusted it differently and tweaked the chit out of the needle stops to make it work right. I have no idea exactly when the change happened or how many 67 model rally panels got the flawed design oil gauge.
By the way, top end oil pressure does fluctuate. Just right low oil pressure would make a oil warning lamp flicker with their i/o sender. Thermal gauges can't respond to resistance changes so quick.