My Cherokee (401) had had low oil pressure for quite a while now. When cold it runs about 40-50 lbs, when warm it drops to about 5-10 lbs at idle and about 20lbs when cruising. I really don't want to pull the timing cover if I don't have to. The motor and pump is stock. The rod and main bearings are fairly new and still within spec.

Does anybody think that just changing the oil pump gears and milling the adaptor smooth will help? What about a high-pressure spring? Would the hand lapped gears help?

Any suggestions besides just changing the cover? (I'm getting an attack of the "lazies!")

Thanks!