350 chev head studs

i have just started removing the heads off the 383 and have hit small snag 2 of the head studs at each end of the heads are recessed quite deep and standard socket has a too thick a wall to get down. I have tube spanner which is thin enough to get onto the nut but it lacks the strength to get them undone. Is there a high strength thin wall socket people use or do they just grind a 5/8 socket down?

cheers