12480147 - Splayed-Valve Cylinder Head ("Semi-Finished")

The splayed-valve cylinder head has 240cc intake runners. The splayed-valve casting has a .240" minimum port wall thickness that permits extensive modifications by cylinder head specialist seeking even more airflow. The intake valves are angled 16 degrees to the deck surface and tilted 4 degrees. The exhaust valves are 11 degrees, with a 4 degrees tilt. This cylinder head has symmetrical intake and exhaust ports and can accommodate a 2.20" diameter intake valve and a 1.65" exhaust valve. Its nominal combustion chamber volume is 45cc, although the actual volume will depend on the seats and valves installed. It is the same cylinder head as cylinder head P/N 24502517 except as follows: No head bolt holes, dowel holes,intake bolt holes, valve seat machining, valve spring seat machining, pushrod holes, or rocker bar machining. This gives maximum deck surface and the end surfaces are machined. Does not include seats or valve guides. The intake valve location moves the valve .050 closer to the bore center line than the earlier P/N 10185040. The following items are available from GM for the installation of this cylinder head: Rocker arm stand P/N 10185041, Intake gasket P/N10185042, Rocker cover gasket P/N 10185043, And Rocker cover P/N 10185045. The intake manifold and remaining valvetrain components will have to be purchased in the aftermarket or be fabricated.