I did not have to take the Cams off to fit the socket on. But my ARP stud nuts were a 14 mm 12point socket. It was a tight fit around the no2 cylinder. It actually got stuck. Had to use vice grips to get it out. But not to much trouble.
I'm half way through doing a head gasket job. I'm doing the same thing you did. I was wondering if you had to take the cams off the head in order to get the 7/16 12point socket on the stud nuts. I noticed it was kind of tight around the intake no2 cylinder one with the 10mm hex I used to get the stock ones out. Did you use a thin wall socket.