I have the Hanger 9 RV-8 powered with an OS 55AX/Bisson muffler and 12 x 6 prop. This engine fits completely within the cowl. I use a remote glow setup and only had to trim the cowl for exhaust, cooling and high speed needle access. It's a great combination and this plane handles windy days well. Use full flaps when landing to slow down as this is a fast airframe. I've had this plane for a year and it's still one of my favorites.

Mike