can someone tell me how easy it is to change one of the studs that hold the exhaust manifold to the cylinder head.i have been told that the cylinder head will have to come off thanks

 

What model are you talking about, and is the stud still in it's original condition....IE Not broken flush with the head. If it is a 924/44/68, and the stud is in good shape, then you can double nut it and turn it out, or use a vise grip and turn it out. If it is broken flush with the head, then the best thing to do is to pull the head and take it to a machine shop. You could try getting an angle drill in there, or weld a nut to the stud and try turning it out, but odds are the head will have to come off.