Possibly an Aero engine of sorts by the looks of it.
A tip if I may. It is better to try and give your posts slighly different names to avoid any confusion. I see you have 3 posts with identical titles although they are in different forums.
Re engine ,looks like a scratch built 3.5 cc rc model car engine . Definitely not a commercial engine.Did see a similar engine described in ME magazine a good few years back. Just for interest the modern equivalent 1/8 scale 3.5 cc engine is capable of producing 2bhp at 40000 rpm ! Yes that’s not a mistake . Top speed about 70mph .Cost for a top class racing engine around £300. Fantastic hobby .