This is for 2 GM SBC 400 #3973493 Heads Bare they have been Milled 15 Thousands, cut for 2.02/1.60 Valves Have Bronze Guide liners, have been checked for cracks have none . I warranty my heads not to be cracked and rebuildable for 90 Days or Full Refund! these heads will work on 350 355 383 most all SBCS . They have mild port and polish work that have surface rust that will shine Right UP with just a little Cleaning NO Reserve!