911 low to no oil pressure
 

I just bought and started working on a project 1969 911T. The motor starts. After changing the oil, fuel, filter etc (before 1st start) put in 8 quarts. The oil pressure was a bit low at idle. It went up when raising the rpm. Now it shows almost No pressure. It is on a gauge not a light. How do we test for the real oil pressure to be safe? If it is low what do we check next? Last question for now. How do I see what this car came with originally? Is there a website/database?:cool: Thanks in advance for any suggestions.