Good sounding muffler for 225 cui

halfafish said

If you're going to replace the pipe, I'd go with 2-1/4" all the way back with the same size muffler, if your engine is stock. Are you running the stock manifold? If so and you have a reason to remove it, hogging out the exit hole to match 2-1/4" will help it breathe a lot better. I used a Dynomax Super Turbo on mine, it has a nice sound and does not drone.

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I've done that to a few /6 manifolds. Before you grab the grinder, get a spare manifold to pipe gasket and bolt it on with a couple of heavy washers under the bolt heads. Compare the "concentricity" of the exhaust outlet hole relative to the attachment bolts.
One of the manifolds that I opened up was way off center l. I had 1spot I barely had to touch, basically had to grind heavily on about 3/4 of the way around,
With the manifold upside down and the flange bolt holes at 3 and 9:00 I had to grind the most at between 10 and 11:00 position and barely any at between 4:00 and 6:00.
You don't want the pipe flange to overlap a cast iron edge.