Quote:

Hey spfan - Since you mention it, we recommend Shell Rotella T Triple Protection 15W-40 or 10W-30 motor oil for your Packard. Both viscosities are rated for gasoline engines as well as diesel engines with an API CJ-4/SM rating. They are formulated with a higher amount of anti-wear package (zinc) which is ideal for muscle cars with high compression hot rod engines. This also applies if you're utilizing high profile camshafts with solid and flat tappet lifters. Hope this info helps! - The Shell Rotella Team