These small block Chevy splayed-valve aluminum cylinder heads are a radical departure from standard in-line valve heads. Their splayed-valve arrangement angles both the intake and exhaust valves inward toward the center of the combustion chamber, allowing maximum valve sizing to dramatically improve airflow without increasing bore diameter. Castings have a 0.240" minimum port wall thickness so, for even greater flow, extensive modifications can be made. Sold individually, these aggressive all-out competition cylinder heads are designed to get the most power from your small block Chevy with no regard for "streetability." NHRA Competition Eliminator participants routinely produce over 1000 horsepower (naturally aspirated) with these race cylinder heads.