I think the G38 is the wrong engine for that. You want to keep it as light as possible and you would have to create a unique mount for it or any other "stand-off" type mounted engine. I would look for an engine with beam mounts so you can use a typical engine mount and that would make it easier to install plus you could use the original nacelle/cowl.

May want to look at something like the Evolution 33GX:
http://www.horizonhobby.com/products...ngine-EVOE33GX

Or the CRRC 26 or 40:
http://www.crrcpro.com/product_show.asp?id=229