There is going to be more to swapping back and forth based on fuel grades than just flipping a switch. I doubt you'll even have the same timing setting on the 87 octane tune-up as you would the higher grade, and probably not even the same jetting. Like Stroker said, pick 87 octane or premium grade, not both! You definately need a 3/8" fuel line from the tank to carb which ever fuel you choose to be on the safe side.
