Is the bolt a socket head cap screw with internal points requiring an allen style wrench or like a hex headed bolt with external points? If it is the later, the standard 12 point socket in most tool boxes will work. If it is the socket head cap screw, you will need a special socket like the hex bit sockets but with 12 points. Long ones are available in order to get above the camshaft. Bought mine from Baum Tools, but other tool sources will have them.