Glixal ATMT1-009-2 Chinese Scooter High Performance Racing 23mm Big Valve Cylinder Head GY6 80cc 47mm for 139QMB 1P39QMB Moped ATV Quad Go Kart (Non EGR Type) Valve Length-64mm Intake Valve Diameter- 23mm (Stock is 18.5mm) Exhaust Valve Diameter- 20mm (Stock is 16mm) Combustion Chamber Diameter-47mm This a Non EGR Head, Does Not Have the EGR Port