wrote:
Please advise which way the exhaust stack openings on a Continental
O-300D should point. After viewing pictures on the web, I have seen
exhaust stacks with the openings pointing into the oncoming airstream
and also with the openings pointing toward the rear of the aircraft.
Also, if the openings are pointing toward the oncoming airstream, will
this affect the horsepower output of the engine?

Thank you,
Shawn McCarthy

The opening should point forward to keep the exhaust away from the
cowling. Horsepower is not affected.

Dan