I assume your talking about the long bolt thats runs through the lengh of the muffler. I would go to the hardware store and get 2-56 threaded rod or even 4-40 threaded rod and get those nyl-lock type nuts and make your own. If you tighten them too much they will break when the muffler gets up to temp. I'll just tighten them enough so the muffler is tight and go a little more.