Viscosity would be whatever weight gives you an
oil pressure reading of 55 psig to 60 psig at 6Krpms when the
oil is at 212F. Anything more is not beneficial and may even be detrimental.
$12.00 for break-in additive, $24.99 for 5 quarts Mobil 1
synthetic 10W40 high mileage (has extra
zinc and phosporous) than standard.