Reinforced Crank Pulley Bolt 1968-73 (510) 1970-83 (240Z / 260Z / 280Z / 280ZX)

This is a replacement bolt for your engine. No matter how tightly an OEM bolt is in place, during high RPMs they tend to loosen or possibly warp. If this happens, it can damage the oil seal and or the crank pulley and thus leading to other kinds of engine trouble. But this reinforced bolt will not come loose and will protect your motor from these types of accidents.