This LS alternator bracket fits the 4.8, 5.3 and 6.0 iron block engines with the iron lower stock pulley. It mounts to the upper port cylinder head with the 2 supplied metric bolts. The bracket fits the Denso style 7si case alternators with 2 options available. The 70 amp 602-20112 and the 100 amp version 620-3146. This is available as a bracket only or as a kit which includes the bracket, alternator, and belt which is part number 625-8551.