Chev Holden LS Pre 2004 ARP Pro Series Cylinder Head Bolt Kit # 234-3601Chev Holden LS Pre 2004 ARP Pro Series Cylinder Head Bolt Kit # 234 3601 SBC LS 03 & earlier hex head bolt kit Fastener Style: Bolt Undercut Stud: No Head Style: Hex Fastener Material: Chromoly Fastener Color: Black Washers Included: Yes Quantity: Sold as a kit. ARP Pro Series Cylinder Head Bolt Kits The Pro Series cylinder head bolts from ARP are cold forged to ensure molecular integrity. They are heat treated prior to thread rolling and machining,