Part Number: EDL-604519 Cylinder Head Style: Assembled Cylinder Head Material: Aluminum Cylinder Head Finish: Polished Combustion Chamber Volume (cc): 110 CNC-Machined Combustion Chamber: No Intake Runner Volume (cc): 290cc Exhaust Runner Volume (cc): 110cc CNC-Machined Intake Runner: No CNC-Machined Exhaust Runner: No Combustion Chamber Style: Semi-open Intake Port Shape: Oval Intake Port Location: Standard Exhaust Port Shape: Square Exhaust Port Location: Standard Intake Valves Included: Yes Intake Valve Diameter (in): 2.190 in. Exhaust Valves Included: Yes Exhaust Valve Diameter (in): 1.880 in. Valve Springs Included: Yes Maximum Valve Lift (in): 0.700 in. Outside Diameter of Outer Spring (in): 1.540 in. Damper Spring Included: No Number of Springs Per Valve: Single Retainers Included: Yes Retainer Material: Steel Locks Included: Yes Lock Style: 7 degree Valve Stem Seals Included: Yes Valve Stem Seal Style: PC seal Rocker Arm Studs Included: Yes Rocker Arm Nut Thread Size: 7/16-20 in. Rocker Arms Included: No Rocker Arm Nuts Included: No Guideplates Included: Yes Guideplate Pushrod Size: 3/8 in. Valve Cover Mounting Style: Perimeter bolt Accessory Bolt Holes Drilled: Yes Valve Guides Included: Yes Valve Guide Material: Manganese bronze Valve Seats Machined: Yes Valve Seat Machine Style: 3-angle Valve Seat Material: Ductile iron Steam Holes Drilled: No Oiling Style: Through pushrod Machined for O-Ring: No Heat Crossover: No Quantity: Sold individually. Notes: The spark plug location has been moved .150 inch closer toward the bore center. Custom pistons are recommended make sure to check clearance before final assembly Bolt-on power, right out of the box. These Edelbrock Performer RPM aluminum cylinder heads feature threaded inserts in the rocker studs and exhaust manifold bolt holes for superior strength and durability, plus hardened seats, bronze valve guides, and fully machined valve cover rails for a more consistent gasket seal. They offer improved power throughout the rpm range for greater throttle response and top-end horsepower. The intake and exhaust runners are CNC-machine profiled for superior flow and performance