Lucas Oil Quality
I know some guys run the half quart of it with changes. I would rather do it as an additive rather than trying to bandaid a dead motor. My engine was 50psi at cold idle with 15w-40. Wasn't good enough for me because it got worse with heat and rpm. Tore mine apart, had debris in the screen (rtv), and i bumped the relief valve spring and i picked up 25psi across the board :D