NOS Engine Expansion Plug Kit Pioneer PE-121 GMC Engine Block Plugs For use on as per package: 8 cyl. 305, 351, and 401 Eng. This is still sealed. This part is part of a machine shop inventory. They were cleaning out some of the old inventory. These are in new old stock condition. Might have been out of box and handled which leaves finger prints but still have factory boxing and doesn't affect use. Please make sure these will fit your application and please check out pictures. Pictures are worth a thousand words. Ask questions before buying.