New oil pump, low oil pressure 1966 289 4V
Hello, we have been cleaning and restoring our '66. The old oil pan was dented badly so decided to change it. While the pan was off, we decided to swap the oil pump as well since we have only owned the car a year and don't know the history. We swapped hoses, transmission lines, cleaned up power steering and all components, cleaned the distributor, changed transmission fluid, radiator fluid, and went from 15W 50 oil to 10W 30. Finally found TDC last night and started the car. When sitting at idle, the oil pressure was a little less than halfway across the guage. After the engine warmed up and we took it for a spin, noticed that the oil pressure was almost down to the first hash mark of Low...not quite in the warning area, but almost. Before we made all the above changes, the oil pressure was about halfway between low and high when running. Could the grade of oil really make such a difference in pressure, or could our new oil pump be bad, or what else could be going on? BTW the car still runs very hot...between M and P on the temp guage when warmed up. Any ideas of where to start looking (with the least amount of taking apart) would be appreciated.