Finally got my rebuilt 401 installed. 45lbs @ idle cold. 20 pounds warm. BUT - 4-6 lbs at 3000rpm. At speed the pressure goes down when the engine is warm. No knocks or rattles. I replaced the gauge with a new mechanical set - same readings. What the hell? Does this sound like the timing cover worn or just lots - too much - clearances?
I have a similar problem. My engine shop has suggested that I check the oil pressure relief valve on the oil pump cover. I'm going the junk yard to get a different cover this weekend. My spring and valve were both new with the oil pump gears. I sure hope it works.
THE DIFFICULT WE DO IMMEDIATELY, THE IMPOSSIBLE TAKES A LITTLE LONGER...