OK, I am in the process of restoring the emissions stuff on my 91 LX 5.0 due to recent strict inspection. I found all of what I needed on e-bay (thermactor tubing). My question is, how does the pipe that go to the back of each cylinder attach? There are spark plugs filling the holes there now, so I am assuming it is a threaded hole, but on the tubing I have there is no bolt or threading attachment. There is a (possible) mounting hole on the ends of the tube right near where the air passes through.