The pin drive wheels we used on the race cars used one large nut in the center that was approximately the same size thread as the knock off. The torque spec was 450 ft/lb if I remember right. A 1/2" impact could conceiveably do it, but it would be easy for a 3/4" tool. (I've been involved with these things since 1980).
Of course I could always go up to the BIG tool:
http://www.irtools.com/IS/product.asp-en-2916
3.5" square drive, 80,000 ft lb, $49,500. Sockets start at about $2,000 ea.