What you see is a standard 1- 1/2" muffler clamp on a 3/4" tube. Works great. I tried to mount it both ways but found the way I have it here was the best. Just make sure that the front mount bracket is fitted properly, and when clamped it won't be in a bind. A piece 5/16" all thread bent to fit will work, followed with a piece of flat metal aganist the front bracket. 14 gage works quite well and easy to work with.
Another option. In the picture you will see three "U" bolts I bought...got them from Lowe's.. they might have what you need. If you use one of these I'd discard the flat metal part that comes with it as I don't like the thiness of it, and make your own. I also didn't use this type because I felt the the muffler clamp was made from a better grade of material and could be tighten as much as needed without stripping the threads.