Practice mufflers

Leonard, it is a special very high heat paint intended for usage on indoor stoves/furnaces. It is good stuff!

BigBlock, typical Borlas are packed with st. st. materials; these are packed with a ceramic fiber that absorbs more sound energy and as such, they will be quieter and will also have a less raspy tone. They are larger than typical Borlas that fit this chassis so they will be quieter due to this extra volume I built into them. Thank you for the nice comments.