I agree... filters can have an effect on low oil pressure. A simple brand change can get you an increase depending on the check valve & spring pressure in them. Double-D is right (check the Fram Filter Thread). 12lbs is probably ok... I have heard the 10lbs for every 1000RPM rule too. Here is my question: why so low of pressure on a new SBC??? What kind of pan set up/oil pick-up & oil pump? It just seems a little low for a fresh engine. Not to worry- you are getting correct pressure at over 4K though. JMO Rigsby