Planejim,

I'm using a Bisson 70 degree Pitt's muffler. This muffler moves the can itself slightly back so I didn't have to cut the chin of the cowl either. However, the 70 degree rake of the pipes made it necessary to use two of those gray exhaust deflectors to get the exhaust out of the cowl. This combo makes for a very clean installation! I also had problems with not enough pressure to the tank so I added a Perry pump. I'm not sure if this was the mufflers fault or one of those nagging OS.91fx problems you read about. Anyways, the plane really moves and I will start experimenting with prop size once it warms up around here a bit. I started with a 13x8 apc that OS suggests on their web site.

Jeff