Some Unocal stations in CA sell 100 octane unleaded race gas from pumps, but, I didn't know that a similar fuel was available from Shell.

The current 100 PON is equivalent to a 104 to 105 RON fuel from the sixties, so it would be okay for an L-88 Corvette, which had a CR of 12.5:1 and required a minimum of 103 RON.

Duke