Standard Size or 1mm larger Includes Intake and Exhaust 16 piece kit. Supertech Extreme Flow Performance Valves for Pro Street and Racing are engineered for High RPM and High HP. Extreme Flow Valves outperform any other valve on the market today, and with their Nitride Coating are perfect for High Temperatures (and run cooler which improves value life), Nitrous, Turbos and Superchargers. **EXHAUST SIDE IS INCONEL******