Here's one that runs great and I've flown on a Veco Tomahawk(?). The mod gets the exhaust port onto the "right" side, and for those who believe we should've always been flying clockwise due to the direction of engine rotation, you now have a reverse-rotation engine to go with your clockwise-trained pilot reflexes. Best of both worlds....
Of course, there is the bonus of getting the needle valve away from the prop which is always nice. This one advantage would have been enough to convince me, but wait--that's not all! The fuel line from the tank can now be shorter, and helps a bit with easier fuel draw regardless of plane orientation.
Somehow in the confusion of bolting it all together, the first few flights actually had the reverse rotation prop on backwards. No matter, the plane just motored on....
Dave
PS--for those that might worry about losing ram air pressure into the venturi--don't. We fly lots of racing engines with things turned around, even on profile ships and it's not an issue at all....