Derf
Addicted to ArboristSite
The opening on the muffler is slightly smaller than the gasket. You can open the muffler up to the size of the gasket, but if you go bigger than that its a lot of work. The muffler is just a thin sheet metal shell up till you get to the size of the gasket, pretty easy to dremel the opening larger... after you get larger than the gasket it's reinforced steel, and its a lot more work to open up.