this is the correct engine for a brutsch mopetta. (only the pull starter handle looks like it has been taken from another ILO engine, probably the 150ccm)
the ILO G50 with 3-speed gearbox is very very rare, I don't think you will have much more chances to get one of this !
When I sold my other ILO 3-speed engine, a couple of years ago, it fetched a much higer price, even this one was far away from beeing restaured...
best regards
Oliver