Re: What\'s that clicking?
I can not be sure of your problem, but it may be a header leak. If it sounds as if it is coming from the glove box, then your exhaust is right there. A leak in the header (exhaust manafold) would make a clicking sound.
Best thing to do is get a piece of 1/4 inch hose, put one end to your ear and the other end probe around your headers and flanges where the Y-pipe connects. Do this while someone revs the engine slowly. If you start to locate a leak it will get louder the closer you get to it. And you will know when you find it.
Ofcourse, that is if that is the problem. Yet, it is a good chance the clicking you are hearing is an exhust leak around the exhaust manifold.