Except it won't being a complete vaporware.

Thanks, I've watched his two videos on leaded gas and difficulties of developing new aviation engines. My thought was that since modern engines aren't made for extreme performance you could detune them and use lower octane fuels. But since 100LL was probably widely available and there were no concerns about lead there was no reason not to use it otherwise a manufacturer just crippled their engine design.

Interesting. In auto world bore being larger than stroke is usually a sign of high-revving sport-ish engine.

What I meant by "advanced" was that modern aviation have rather low specific output compared to automotive engines where you could have a 200hp/liter engine in a Toyota so they don't have high compression ratio and/or boost pressure. And these highly efficient engines run on say 98 octane unleaded

I guess even if the engine is made yesterday it still made with obsolete tech by automotive standards. As far as I understand there was no push for advanced engine tech like fuel injection and ECUs in GA after WW2 neither from customers nor from regulators because whatever was available was good enough and all high-performance applications switched to jets.

Why do we even use avgas with aviation piston engines being what they are today i.e. not particularly advanced? Is it regulations, so engine certified for 100LL couldn't be easily switched to a fuel with less octane number?

But with avgas being just 0.14% of all fuel consumption in US I guess it's not a national issue though people living near small airports could be concerned.

Real life "Three Days of the Condor"?