There is a recent post on one of the Thunderbird forums, regarding the gas mileage of 55-57 Thunderbirds with 292-312 Y-block engines. Some owners reported 7-10 mpg, others getting 9-12, another getting between 13-14, and another claimed 20 mpg on the highway, in overdrive. Having inherited my 55 T-bird, I drove it just a couple of times before beginning restoration, so I have no idea what kind of gas mileage I should expect. 7-13 mpg is nothing to brag about. Are these numbers typical? They are awfully low for a small v8 in a 3,000-lb. car. Is there an explanation, other than the given examples are parade cars that are seldom driven on the highway? 

While we’re on the subject of gas, just filling my 55’s tank is a crap shoot with lack of back pressure causing gas to overflow. Has anyone come up with a circumvention?

1955 312 T-Bird Warwick, NY

I used to watch and listen (instead of trusting the pump auto-shutoff), and fill until I could see gas in the filler-neck.  Bad idea, since my tank’s neck must leak now at the attachment point.  If I do that and drive straight home from the gas station, the garage will stink of gas next day.
Since the pump usually shuts off before the level gets high enough to splash, I trust it now, but do watch in case I have to wipe-up any spill.

6 VOLTS/POS. GRD. NW INDIANA