RE: Gas Engines
To switch to gas; Every piece of fuel line and stopper needs to be changed to either Tygon or Neoprene. Evan the stopper in the tank needs to be replaced with a gas compatible type. Otherwise the gas will disolve them.
The engines run very much the same and sound pretty much the same. They both have an idle adjustment screw and a high speed screw. The main difference is the gas engine has a built in fuel pump.
Search these topics here to read up on gas engines. Also you can go to Tower Hobbies website and pull up airplane build manuals to see what instructions are given for installing a gas engine in their planes.
Magneto
CH ignitions
Gas stopper
Gas tank vent line
Diaphram
Engine standoffs