A squared says
I've just solved the aviation leaded fuel issue: Simply remove all the lead and retard the ignition on all the engines.
You forgot the reason lead is added to fuel. It's to stop detonation during the normal power range of a properly timed engine. You could certainly correct the timing BUT at high power settings combined with a hot day and or a long climb you would get detonation if the octane rating was too low. The lead slows down or stops auto ignition ahead of the flame front. It's a public holiday here in Australia for QE2s birthday. Having toasted her health you're doing my head in answering technical issues this late in the day.
