Edelbrock 8552 Head Bolt Kit Hardened and parallel-ground washers are included with 170,000 PSI Bolt diameter of head bolt kit is 7/16 Reduced head eliminates the need for valve train removal Used on the following Edelbrock heads: EDL-6022, EDL-6025, EDL-6032, EDL-6035, EDL-6037, EDL-6039, EDL-7716, EDL-7721, EDL-7728 and EDL-7729 Can also be used with 351W heads on 289-302 block as long as EDL-9680 bushings are also used