The pic above shows it . You have to pull the cover that the oil filter screws onto off. Under it is the gears that make the oil pump. If there is too much clearance between the gears and the cover, oil pressure and volume suffer. Earl Brown, inventor of the Earl Brown oil pump mod has been posting. If you search earl brown oil pump mod you should get plenty of info on the subject.
Usually I just check the clearance with plastigauge. If it is too much I rub the cover down with fine grit sand paper on some glass to flatten out the cover and take up the clearance. Ta performance sells gaskets of different thicknesses to set the clearance.
I don't have a manual in front of me so I'm not sure of what the clearance should be. I'm sure someone will post up.
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