The stock muffler,.. doesn't use a a waffle baffle type muff...
It is chambered... exhaust enters the pipe, but is blocked in the middle and forced through holes into a surrounding chamber, then down, and back through more holes to the exit pipe... This is a lot quieter than just a waffle with some packing around it...
In a waffle baffle,.. the air passage is just narrowed a bit and disturbed by protruding steel fingers as it passes some sound absorbing material... it can have packing, or not,.. but neither way will it be as quiet as a chambered muffler...
So,.. what I was suggesting was to put the waffle, in front of the muffler, in the exhaust pipe,... kinda' a double muffler system...
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