fitting AU engine to ef/el is prity easy all you do is cut a bit off your xmember out to fit au sump and reweld the face change wiring on engine replace ef dizzy coil pack dont have to set up TDC crank angle sen picks it up.try and use as much ef accs as you can very good power up grade for ef/els any more mods anyone knows i would like to know as i do all this sort of thing for hobbie