Sinclair HC sign

The first high-octane gasoline. In 1926, Sinclair leapt ahead of most of its competitors with H-C, the industry's original high-octane premium gasoline for motorcars. The 72-octane auto fuel, developed at its Houston refinery, was better than anything then marketed (Lindbergh's flight to Paris the following year was on 73-octane gasoline). H-C stood for "Houston Concentrate," though some advertising men called it "High Compression."