Pontiac 400 oiling problem

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Pontiacs have a thrust plate on the cam so unless very wornit shouldn't be cam walk issues(and if so alot of metal in the oil).

Which oil pump is in it? The 78 pumps had less pressure than the Ram Air replacement ones-I could see my 78's original pump bouncing the gauge when cruising. Even the RA replacement pumps come with a weaker spring also to get close to those lower pressure ones. Sometimes a piece of trash get stuck between the bypass ball bearing and doesn't let it close completely so basically a pressure leak there-not uncommon,why some guys use a smaller ball bearing in the bypass and a 0.060 shim behind the spring to take up the difference on the spring tension.



Bearing clearances? Excessive clearance(on most of your bearings) also create kind of a "leak".