RE: BUSA Fokker DVII
The muffler exhausts through the top of the engine compartment. I used the stock "pancake" muffler that comes with the G-38 engine. The only complaint I have heard about the DVII is that it needs some down thrust to the engine. I used one washer under the top two motor mounts. If you put in right thrust you will have trouble lining up the prop shaft in the cowl.