Go to the GM dealer and buy supercharger oil. The Eaton supercharger timing housings only have gears in them, and the oil is never exposed to products of combustion, so a gear oil is appropriate. This is why the stuff should stink like a gear oil. Later model Eaton's went to 83-tooth timing gears to deal with noise complaints, and the large number of fine teeth turning at 12,000 rpm make them excellent for shearing the oil.