SSW,

I'm in the process of installing a Zenoha G-26 on a KMP Beaver. I didn't go with a Bisson inverted wrap around on mine because the muffler is too wide and would require cutting out the bottom and sides of the cowl pretty good and atleast 1/2" spacers behind the engine mount to get the muffler to clear the firewall. I have a setup like that on my P-6E and it still stuck out the sides of the cowl bottom being as big as it is. Part of the problem with the wrap around inverted muffler on the G-23/26 is the mag housing behind the cylinder. The muffler drops down farther than normal to clear it. It can be done depending on how particular you are with cutting up the cowl.

I'm trying to come up with a custom setup using a G-23 muffler and 1/2" copper piping and fittings to route the exhaust down and out the right side at full scale exhaust exit location.

Or you can use a B&B muffler or the stock G-26 one but it's going to look ugly sticking out the front side of the cowl.

The G-20 muffler would fit in the cowl with only the pipe sticking out the front side but then there is a problem with installing the cowl over the engine with the muffler and carb attached unless you modify the muffler and change the exit pipe location to the side and down and out like the G-23 muffler.