My research shows Viton is the best O-ring for gasoline. Nitrile (Buna-N) is the next best for gasoline.
I bought the Viton set of O-rings at Harbor Freight for around $10.00. It has around 200 O-rings in various sizes. The A011 7.65 x 1.78 worked for the fuel filter. There are 10 of that size in the set.
I still can't believe that the filter manufacturers don't have that information on their website.
[This message has been edited by Carrolles (edited 06-30-2013).]