Thanks - I understand your oil pressure testing process. I already have installed a mechanical fuel pressure gauge which works great - now I will add the oil pressure gauge. Good thing is, in an emergency case you can close the port with a cap.I don't know how a permanent mechanical gauge would hook up so I don't know if this would work for you. I know that my OTC mechanical oil pressure tester screws into the capped port you see in the first picture. The second picture is the hose from the OTC tool.