[Synchro909]

On my way to the National Rally in 2014 (a 2,000 mile trip), the rear clamp disappeared somewhere and the whole exhaust was dangling by the manifold clamp. Fortunately, someone saw it (from behind me) and told me about it. I immediately bought a new clamp from a vendor at the meet and installed it. It was one of those padded things and it didn't get me home again before it was rattling so badly that pedestrians knew I was coming from miles away.
Since then, I have used a different method of holding the rear end of the exhaust. I have seen a rubber ring used - like a modern car but I use the original clamp with a spacer so that it can't be done up tight. I wrap a piece of paper or cling wrap around the pipe where it will be in the clamp and load it with plenty of silicone. I choose a variety that sets fairy hard. I put 3 or 4 wooden match sticks in it and clamp it up so that I have a layer of silicone that thick all around the pipe. Once it is set, I trim it (fussy, I know) and drive on. The paper or cling wrap means the silicone doesn't adhere to the pipe and it can slide through it. The paper burns off quite quickly and I'm left with a silicone pad to stop the rattles. I have to redo it every 20,000 miles or so but that's fine by me. Never a problem since.
BTW, I have read many times here that the manifold tends to sag because of the weight of the exhaust hanging on it. I believe that is only half of the problem. If the rear clamp is too tight, as the exhaust expands, it will push forward on the manifold and add significant force to it in such a way that it can't help but bend. The pipe MUST be able to slide through the clamp