RE: Engine size comparison (SPE26 & G20EI)
My G23 is just about the same physical size as a SPE 26, and though it's been given the Ralph Cunningham (RC Ignitions) diet treatment, it is still quite a bit bigger than my G20.
The standard Zenoah muffler cannot compete in both weight, size and performance with the lightweight Scott Ellington unit offered on some SPE engines, and using one of these will significantly increase the G20's performance.
Also using one of Ralph's thinner and stronger carb rotator blocks which is 3/8" thk. significantly reduces the amount the carb sticks out from the engine while allowing for a straight forward throttle setup.
Karol