Part Number: EDL-60489 Cylinder Head Style: Bare Cylinder Head Material: Aluminum Cylinder Head Finish: Natural Combustion Chamber Volume (cc): 100 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): 1.890 in. Valve Springs Included: No Maximum Valve Lift (in): 0.700 in. 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: No Valve Seats Machined: No Steam Holes Drilled: No Oiling Style: Through pushrod Machined for O-Ring: No Heat Crossover: Yes Quantity: Sold individually. Notes: Spark plug location has been moved 0.150 in. closer toward the bore center 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