Brand: Edelbrock Product Line: Edelbrock Performer RPM Cylinder Heads Part Type: Cylinder Heads Part Number: EDL-60449 Cylinder Head Style: Bare Cylinder Head Material: Aluminum Cylinder Head Finish: Natural 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: No Intake Valve Diameter (in): 2.190 in. Exhaust Valves Included: No Exhaust Valve Diameter (in): 1.880 in. Valve Springs Included: No Damper Spring Included: No Retainers Included: No Locks Included: No Valve Stem Seals Included: No Rocker Arm Studs Included: No Rocker Arms Included: No Rocker Arm Nuts Included: No Guideplates Included: No 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