I was gassing up the 78 yesterday. The gauge showed less than half a tank. Doing the math, I came up with 12+ gallons needed. The pump shut off at about 8 gallons. I knew that was too little, so I waited a moment for the air pressure to ease and continued pumping. It hit 12 gallons and kept going. Ah-ha, thought I. I was right. However, at about 12.5 gallons, gas spilled out of the neck and onto the ground. I shut it off immediately. No gas got on the paint. I had a nice little pool of gas around the filler, but I got that sopped up. So I have to ask, "Why didn't the pump shut off again as it approached full?". Must I listen for the cahnging sound as it fills up, or live with a less than full tank?