Affordable maximum power cylinder head for competition and ultra high-performance street. 530-580 hp potential, out-of-the-box, for a cost effective, race-winning set-up. 64cc chambers yield about 12.5:1 compression with a 12cc domed piston in a 350 V8. These cylinder heads feature angled spark plug holes and accept standard 23° valvetrain hardware. INSTALLATION NOTE: Check cam manufacturer's specs for compatibility with valve springs for spring rates. Match with Edelbrock head gasket sets. Use Head Bolt Kits for easy installation. These heads require the use of a 14mm x 3/4" reach, flat gasket spark plug with a heat range appropriate to your application. Deck thickness: 9/16", rocker stud diameter: 3/8", pushrod diameter: 7/16" (width of slot in guide plate).