Edelbrock 8591 Head Bolt Kit Hardened and parallel-ground washers are included with 170,000 PSI Head bolt kit has a 12-point head Cold-formed to ensure molecular integrity and heat-treated prior to thread rolling and machining Used with Edelbrock heads: EDL- 60919, EDL-60929, EDL-60149 and EDL-60189 Reduced head eliminates the need for valvetrain removal