Fuel isn't one-size-fits-all. A modern race engine and a 1965 straight-six Healey want completely different things from the liquid in their tank — and picking the wrong one can cost you power, or your engine. Here's how the two categories differ, and how OlioClassico approaches each. What racing fuel is for: Racing fuel exists to let an engine run harder than pump fuel allows. Motorsport engines run high compression ratios, aggressive ignition timing, and sustained high RPM —