Following your project with interest as I have one that is in worse shape then yours. How much $$$ do you think you will have in it when it is done? I have been searching for stock mufflers that can be modified. The main problem is the size. I have found some Kabota B1500 and BX1800D mufflers that might work. The best I think is a Walker Tractor muffler #21188. It is 4.25" round and 11.25" long. I know the round size will work but don't know about the lenght.