My exhaust is exhausting me

[Ken Cunningham]

Any advice, general or specific, about how to get my exhaust system to quit banging? My problems started when I put on a test pipe so I could run leaded fuel at the track. I kept the straight pipe on since I just passed my biannual smog and expect to be back to the track soon. But then my down pipe started rattling on the frame. I tried a couple of times to loosen the clamps, put a piece of wood between the frame and the d/p, tighten everything back up, and remove the wood. As soon as I drove a mile or two, the d/p would still drop down and start a very annoying rattle. So I reinstalled the cat. Now my exhaust rattles on the frame and rumbles where the muffler hits the frame! I have a 3" down pipe (ATR, I think), and a dual muffler set up (probably also ATR, they were on the car when I bought it). The darn thing was quiet until I started to mess with it. My approach so far has been to loosen up every connection, put some wood spacers in the contact points, tighten everything front to back. I hate exhaust work. A rattling exhaust system just takes the fun out of driving this sweet car.