Ok, heres confirmation. They are definatly oldsmobile heads. if they came from a 350 from a 73 smogger motor, your not in too good of shape. However, if they are from a 72, thats a whole nother story. the 72 heads were made with larger valves and cleaner runners, and are very desirable for someone looking to build a 403. In either case, if you find you cant use them, take them to e-bay. The oldsmobile hunters are looking