I bought a 61, several months ago. I have never been able to put more than 12 gallons in her. Several times, I drove it until the gauge was bottomed out[as far as i could tell]. Always carried a can with a gallon. I thought the gauge was messed up. It would show full, when it would take no more gas but, it would run real low after 10-13 gallons. The tank looks good and original, and undented. I thought, these cars used at least 20 gallon tanks. Anyway, of all the times to finally run out, it was during a nasty storm on Sunday. Anyway, I have been looking forward to a 6 hour drive this weekend, but now I will not take this car. My owners manual says it is more that 13 gallons, what should it really be? I have been told, 9 MPG is standard for a 352 3 spd. and expect that, but I need more than 100 miles before i look for a gas station.