ARP HEAD BOLT KIT 135-3703, BB CHEVY MARK IV W/LATE BOWTIE ALUMINUM IRON DART PRO-1 PRO TOP LINE & WORLD PRODUCTS IRON HEADS, HIGH PERFORMANCE 12 POINT 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.