Looking into a new engine for my next plane and I was wondering if the muffler on the G90 swivels 90 degrees so that it could be used as a Pitts style muffler. If I have to buy a $40 muffler to go with the engine, the Magnum 91FS isn't that much more money. Also, for anyone who runs the G90 with the stock muffler, how's the performance of the engine with that muffler? Thanks.

The G90 performs very well with the stock muffler.

It will swivel all around. you can make it's out opposite the engine head position.