go to the sunoco website and they have a search engine for stations that sell 100 octane gas. many of them sell it.

or you can get a gallon of klotz octane booster for $60 shipped that will make 128 gallons of 95.5 octane or 64 gallons of 98 octane or 32 gallons of 100.5 octane gas. It is a lot cheaper to go that route than to buy 100 octane fuel.