ARP HEAD BOLT KIT 135-3604 BB CHEVY 396 402 427 454 CAST IRON OEM BLACK OXIDE INNER ROWS, STAINLESS STEEL OUTER ROWS HIGH PERFORMANCE HEX HEAD ARP High Performance Head Bolts are available with a reduced wrenching hex or a 12-point and wide area flanged head that eliminates the need for valve train removal to facilitate cylinder head re-torqueing.