RPM CNC PONTIAC D-PORT CYLINDER HEAD 72CC HYDRAULIC ROLLER CAMSHAFT. The Edelbrock #61595 Performer Pontiac Cylinder Head utilize a D-Port exhaust port configuration for use with standard D-port exhaust systems. They are designed for 1962-79 389, 400, 421, 428 and 455 c. V8 Pontiac engines with a 4.060 or larger bore. They feature optimized oil return passages for increased oil flow. The spark plug has been relocated closer to the exhaust valve for improved performance. This head is cast with extra thick port walls and a compact port size, making them ideal for CNC and hand porting. Complete cylinder head includes guide plates, rocker studs and high quality valvetrain for direct bolt-on application. Heat crossover is machined for 50-state emissions legal performance. CARB Executive Order Number. Exhaust 45 deg/Intake 45 deg. EQUIPPED WITH SPRINGS FOR USE IN HYDRAULIC ROLLER CAMSHAFT APPLICATIONS. Combustion Chamber: 72cc. Engines may require notching the block for valve clearance. Three head bolt bosses are raised higher than the standard D-port heights and will require head bolt kit #8561 to install these heads. Deck thickness: 5/8. Rocker stud diameter: 7/16. Pushrod diameter: 5/16 (width of slot in guide plate). (Suggested) 0.3125 in. Valve Spring Maximum Lift. Instant response to any inquiries. If you are not sure this is the correct item for your car, you can send us VIN number of your vehicle, and we will check it for you! If you have any questions about this item, please ask. DEFECT/DELAY If there is any defect or delay? Items should be installed by authorised mechanics. Other destinations might have different tariffs or additional extended area cost. If You live outside Europe? If You have received damaged or faulty goods? United Kingdom, Italy, Germany, Latvia.