Dont forget to put anti-seize compound on the new bolts, this same thing happened to my dad when we went to put a newer 2.8 in his truck and had to replace the exhaust manifold bolts, only the driver side had bolts break off, 3 of them, and used a MAPP gas torch to get them out. One we couldn't so we welded a peice of all-thread to the bolt stud we couldnt get out and made it work.