My gals 93 yj just blew out the cat and needs a replacement. Muffler guy put it up on the lift and there is a hole on the rear most part of the exhaust manifold that looks like it should have a bolt in it, but it doesnt. He also said this could be a port of some sort, or the bolt that was supposed to be in there broke or rattled out. It is in the same area that a bolt would be, and seems to have the same circumfrence as the manifold bolts. Hope yall can help me out, thanks, lane