I notice in the pictures you guy install the engine upside down, can I install it vertical? I am trying to avoid too much cutting on the cowl. It seem there is a lot of top space for the cylinder and the plug. Do I need to add any side and down thrust?

The instructions do not mention making any thrust changes. The instructions don't suggest or show how to mount the gas engine. The instructions do show a 4 cycle mounted sideways, but I think your on your own as far as trying to do that with a gas engine.

The only comments on the gas installation is make sure you use good stand offs for G23 or G26 engines to make the 6 1/8 ".