The data block on the Flying Heritage Collection’s P-51D Mustang includes the phrase “Suitable for Aromatic Fuels.”
What? I thought all gasoline was smelly. Actually, aromatic additives (usually benzene, toluene, and xylene) were used for high performance engines like the Merlin to wring out every last bit of horsepower in combat situations. Aromatic fuel requires a fuel system that can handle the additives.
It was unwise to put high performance gasoline into a plane like the L-4 Cub. “Hotrod” aircraft like the Mustang could handle AAF grade 100 gasoline (or more), filled with its cocktail of aromatics.