Interesting bike, and looks like a good frame, but not a Cinelli and I don't think a Centurion/Cinelli either (but that was a good guess). Your best clue is that L'equipe Delta on the chainstay cause it's likely the model name, and the serial numbers will help somebody...the holes in the seatstays are just for gas to escape during brazing. There are some details that are more "British" or "USA" than Continental....but I sure don't recognize enough to ID it. How about a close-up of the head lugs? Is the BB shell 68mm wide and British threading? Is the brake bridge for a nutted brake?