You can run 91 octane if that's all that available...I recommend nice spark plugs and a complete ignition system upgrade before installing the supercharger...also if you want a larger fuel pump go with the jackson stage one boost upgrade kit...comes with a boost timer, fuel pump, new sparkies, larger crank pulley, and a new thermostat. Plus I heard venom fuel injectors are complete crap, remanufactured crap that is.