The Edelbrock part # 79455 Big Block Chevy E-CNC 325 cylinder head is the the ultimate in performance. These cylinder heads are fully CNC ported for maximum horsepower and torque, making them ideal for high-performance street and light duty racing applications. They also feature high-quality lightweight valve springs and heavy duty hardware for maximum lift and maintain the stock exhaust port location. E-CNC 325 FOR B/B CHEVY (OVAL PORT) FEATURES: - Features 24.5° x 4.4° intake valve angle, 15.5° x 4.2° exhaust valve angle - Stock exhaust port locations and spark plug angles have been modified to produce a smooth flame front for increased fuel efficiency and maximum power - Cylinder heads are equipped with high-quality valve springs for valve lifts of up to .700” - Full CNC porting of the combustion chambers as well as the intake and exhaust runners; this improves air-flow and overall performance potential - Equipped with valve springs for use in hydraulic roller applications - Combustion chamber size of 110cc - INSTALLATION NOTE: Match with Edelbrock head gasket sets . Recommended spark plugs are Champion RC12YC or equivalent 14mm x 3/4" reach with flat gasket seat.