Hello, my 79 New Yorker with a 360 has an oil pressure gauge with markings, but no actual PSI marks. There is a high mark, a low mark, and 16 dashes in between. I was wondering what the dashes correspond to in PSI, as I am getting a perfect reading at idle, but 3 dashes from high while doing 70 on the highway at about 2400 rpm. Just thought I would see if anyone out there has an idea. Thank you!