depends on what you term a "better" grade of oil. honestly for these engines i wouldn't worry too much. Most of the changes going on are based on the EPA's doings. The amount of zinc in the oils has been cut dramatically as any that got into the "mix" fouled up catalytic convertors and coated o2 sensors. Owners of older muscle cars etc like myself that have solid lifter cams with high spring pressures, steep lobes etc have to add additives to get the zinc back in or pay through the nose for royal purple, amsoil etc. The zinc sort of forms a protective metal layer in the high pressure metal-to-metal contact areas. The added detergents in the newer oils really aren't all that helpful for older engines. In the last 5 or so years when the oil companies started changing things around the number of competent professional shops and engine builders that wiped out brand new cams on break-in increased dramatically because of the new blends. For these instances, some of the older obsolete (and cheaper) blends/ratings were better.
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