Cylinder Head Specifications: Combustion chamber volume: 59cc, Intake runner volume: 185cc, Exhaust runner volume: 75cc, Intake valve diameter: 2.02in, Exhaust valve diameter: 1.57in, Valve stem diameter: 8mm, Valve guides: Manganese steel, Deck thickness: 5/8in, Valve spring diameter: 1.30in, Valve spring maximum lift: .600in, Rocker stud: 7/16in, Guideplate: Hardened steel, Pushrod diameter: 5/16in, Valve angle: 18, Exhaust port location: Stock, Spark plug fitment: 14mm x 3/4 reach, gasket seat . Match with Edelbrock head gasket sets. IMPORTANT NOTES: The E-CNC 185 cylinder heads for small-block Ford are an all new design that is CNC ported to achieve optimal air-flow for maximum horsepower and torque in high performance street and light duty racing applications. The casting and port designs are all new and engineered for great performance. E-CNC heads feature fully 100percent CNCd intake ports, combustion chambers and exhaust ports for improved air-flow. These heads feature 2.02Gg intake and 1.57Gg exhaust, 8mm stem valves and are equipped with conical valve springs and steel retainers for a lightweight and durable valve train combo. These small-block Ford heads have an aggressive 18 valve angle for maximum performance and accept common intake manifolds such as Edelbrock Performer RPM and RPM II. Deck thickness: 5/8in, rocker stud diameter: 3/8in, pushrod diameter: 5/16in (width of slot in guide plate). Deck thickness: 5/8in, rocker stud diameter: 7/16in, pushrod diameter: 5/16in (width of slot in guide plate). Bare heads will have valve guides and seats installed, but will require final sizing and a valve job to match the valves you will be using. Edelbrock pushrods No.9632 are recommended. Requires hardened pushrods. Pedestal mount rockers