These heads incorporate high-quench combustion chambers which promotes a more uniform atomization of the air/fuel mixture for more power. Spark plugs have been positioned closer to center for more efficient combustion. These heads include stainless steel valves that are swirl polished and have undercut stems for maximum flow. They accept standard or center bolt valve covers, work with most standard exhaust and have intake ports that are .200" taller than typical small block heads. Uses Vortec style intake. Price per head.