The same high Zinc and Phosphorus formula as our original break-in oil, now in SAE 10W-40 viscosity. Well suited for classic muscle car, European sports car and motorcycle engines. Ideal for flat tappet and aggressive roller valve trains, as well as Ethanol blended, pure Methanol and oxygenated race fuels. Does not require additional ZDDP additives. Good for dyno testing, one night of racing or up to 400 miles on the street. Viscosity typical of 10W-40.