From the Summit website:
"
Summit Racing® ZDDP Performance motor oil is a premium, conventional-type engine lubricant blended with advanced base oils and additives. Formulation is developed for street or racing use in all classic car, hot rod, and muscle car style engines. It's available in a single grade SAE30 "break in" and in multi-grade blends. ZDDP works perfectly in all displacements and provides maximum protection in engines equipped with flat tappet and roller camshafts. No additional additives are needed. This oil also provides great protection in high-powered engines equipped with power adders and is compatible with all fuels.
* Boosted formulation of ZDDP (zinc dialkyldithiophosphate) for enhanced anti-wear protection
* Break-in oil is specifically blended for initial break-in of camshafts and rings in high performance engines
* Multi-grades are specifically blended for high performance engines in hot rod, classic, and muscle cars
* Advanced formulation of rust and corrosion inhibitors; meets military storage specifications
* Not for use in vehicles equipped with catalytic converters; meets no API specification"