Glixal ATMT1-012 GY6 50cc to 100cc Scooter Engine 50mm Cylinder Head Assy with 64mm Valves for 139QMB 139QMA Chinese Moped ATV Go Kart Quad (Non EGR Type) Valve Length-64mm Intake Valve Diameter- 18.5mm Exhaust Valve Diameter-16mm Combustion Chamber Diameter-50mm This is a Non EGR Head, Does Not Have the EGR Port