I have a Bennche Bighorn 400. I happened to be checking the fuel pump, and when I looked down, I saw that the donut between the muffler pipe and the exhaust manifold was split, and the springs (I only found 3 of the 4) were all lying there, broken. I purchased a new donut and springs, and installed everything. In order to get a good fit, and to get the springs installed, I had to put something under that joint to prop it up, otherwise it would sag. I used a piece of lumber about 2" thick as a temporary prop. Once I got everything installed, I was able to remove my prop. I think I'd like to put another prop under that joint, just to give it a little extra support. My question is, what could I use that wouldn't cave or burn under the heat of the muffler? Thanks!