D Series Fuel Rail Civic Integra CRX D16 Y7 Z6 Non-Vtec Fits D-Series Si. High Flow Fuel Rail, Fuel Pressure Regulator, and Fuel Pressure Gauge. A custom fuel line fitting is included for the factory fuel line and the ends of each rail are tapped to accept -6 AN or 9/16" x 18 fittings for users who want to use custom fuel lines.