AA 500 Series Casting With seats and guides 40mm Intake 35.5mm Exhaust, It is set up to build the performance Head of your needs.
The 500 Series Castings come STD with: Clean flowing cooling vanes, for maximum cooling through the head, and around the intake ports for increased HP and over all cooling. A modernized Combustion chamber, for increased head flow & performance. A second Full Fin, so you can Fly cut your heads deeper to achieve almost any desired Head CC volume needed. Blocked off rocker stud bosses, to eliminate the O-ring and stop possible oil leaks. Long reach 3/4 Inch Spark Plugs, to reduce the chance of cracking between the Valve seat and Plug.
Casting: AA 500
Valve Size: N/A
Head Bore: 85.5
Plug Size: 12mm (Replacement NGK Number is D8EA)