Chevrolet marine big block aluminum oval port cylinder heads by Edelbrock 601459 Marine Duty Performer RPM 454-0. The Marine Duty Performer RPM heads are black anodized for corrosion resistance and they include heavy duty Inconel 1.89" exhaust valves. Intake valves measure 2.25". Chamber size is 110cc and intake port size is 290cc, exhaust port size is 110cc. Deck thickness is 9/16". Maximum valve lift is .700". Smaller than stock 11/32" valve stems promote excellent flow and lighter valve weight. Made in the USA at Edelbrock's foundry and machined at Edelbrock's manufacturing facility in the USA. Sold with valves only to allow for valve spring choices. Sold As 2 Cylinder Heads Edelbrock 61459 Performer RPM 454-0 Marine Duty Chevrolet big block aluminum cylinder heads 61459 We offer the entire line of Edelbrock Chevrolet big block aluminum cylinder heads. Check them out! We welcome CANADIAN customers! For ordering information, click on "Canadian Order Info" at the top left side of this page. LOW COST SHIPPING! Just $12.95 to ship your entire order by U.P.S. ground within the continental United States. Purchase any quantity of items and you pay just $12.95 to have it shipped! The more you order, the more you save! (Orders to Hawaii, Puerto Rico, Virgin Islands, and some parts of Alaska will have additional shipping charges. Customers located in these areas will be emailed the shipping costs for approval before we ship the order.) We use Postal Priority for APO and FPO addresses only. Additional shipping charges may apply to these addresses.