Just a quick note — I still haven't found a good source for gasoline prices before April of 1993 (if you can give me a URL for this data, I would very much appreciate it!) but I did find the peak price for gasoline in California in March of 1981, the price point quoted in the news articles as being the highest "inflation adjusted" price (until now) for US gasoline.
That price was $1.66 per gallon, and the dollar at the time was worth about 63.6 mg of gold, so gas was around 106 mg of gold per gallon, about the same as the recent low in February of 2007.
Interestingly, the highest price I've found so far for gasoline is 295 mg of gold, back in 1970, when gasoline was selling for 34 cents a gallon (but the dollar was worth 880 mg of gold.)
