Used to run my 67 at the track. When running, had maybe 2 gallons in a fuel cell in trunk and the main tank empty. I would run at tracks quite a distance away and would carry five 5 gallon cans with 110 and 94 as I blended. I usually had 2-3 gallons left in 1 can which leads me to believe 18 gallons to be accurate. The fuel gauges in these cars are not accurate for one and usually calibrated to read less than what is actually in tank.

My T/A and my Cavalier read empty with needle on the line, yet when I fill to full, there is usually a 2 gallon difference between capacity and needle registering completely E on the gauge. I will fill with 12 gallons with a capacity of 14.5 gallons.

I believe it is a positive margin of error so people don't totally run their tanks dry.