Unfortunately, the carb will be sticking out in the airstream. It won't fit inside the cowl. [] Ugly, but plenty of air.

Muffler is a different story. If I use the stock muffler, it's going to be hanging out in the air as well because it's 3x4 and about 2" thick. Not gonna fit inside the cowl. I might purchase an aluminum muffler from www.wackerengines.com . I need to call him and make sure it will fit before I plunk down the $30 for it. If the aluminum muffler fits, I'll use that. If the aluminum muffler won't fit inside the cowl I will cut the stock muffler apart and braze a much smaller chamber that will fit inside the cowl.

I was thinking about the heat too. I'm not sure what to do. Maybe add some of these famous louvers the other guys are talking about? That would pull some air past the muffler. My baffle is not totally sealed. Air can go escape by going around the crankshaft and prop hub. Some of that air should find it's way to the muffler.

I have about 1.5" of space between the side of the engine and the cowl. I even thought about making a custom muffler that would will that entire space (large expansion chamber = quiet) and just have a 1/2" tube exit the cowl near the same place where the cylinder air exits. That space runs from the F2 former to the baffle. Probably 6" long. It's going to vary in height as the cowl slopes up in the front. That space could end up being about 30 cubic inches.