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Oil Pressure Drop


New member
Its been awhile. I have a 400 Pontiac engine block. Bored .3 over. 10-1 compression heads. 4.5 in crank. Everything is new on the engine. When the engine is cold and not moving I get about 40-50 lbs oil pressure. When the engine is warmed and not moving the oil pressure drops below 5. When the engine is warmed up and driving the oil pressure goes back up to 40-50. But when I stop the oil pressure again drops. Thoughts? Thanks . . . JIMB


Staff member
I would start with installing a temporary gauge to verify that your in car gauge is accurate.
When you get the below 5 reading, assuming hydraulic lifters, do the lifters become noisy?
What weight oil are you using?
What brand and part# oil filter are you using?