I had a ‘59 Galaxie with a 292 2-bbl and 2-speed Fordomatic (aluminum case), 3.10 axle, and it would get 14-15 mpg, assuming the odometer was accurate. Thirsty by modern standards but still as good as or better than most pickup trucks that everyone seems to drive these days.

My last tank in the ‘54 was 18.3 mpg. I’m going to try some different rods/jets and see if I can crack 20.

1954 Crestline Victoria 312 4-bbl, 3-speed overdrive

I did not mean Scruby, I meant another brand, it's a beautiful car.

I also have a couple more old cars, a 57 Belair with a 400 small block modified with a 5 speed TREMEC.  It's a gas hog  The other is a 30 Ford Hi Boy with a 53 239 Flattie, three speed with a 330 rear and it's also a gas hog.  My daily driver is a 16 Lincoln 3.5 liter twin Turbo.  It has 365 HP and gets really great mileage. My worst offender of fuel mileage is a 1993 F350 dump truck with a 351 Windsor, AOD and a 456 rear.  Some where around 8 mpg. 

When I bought my old Fairlane, 292 Ford o matic, I asked the seller if it would get 14 mpg and he laughed and said if you are lucky.  I agree with him it will not get 14 mpg, but I don't drive it a lot and most of my driving is in town.  I don't calculate mpg and I also run premium fuel.  I call it a gas hog.

I recently swapped in an edelbrock 1405 carburetor on a 4-hole spacer with 7547 rods (instead of the 7047 it had originally). This is an old, used carburetor in good condition—not new. Average MPG for the two tanks since I bolted it on is 16.98, driving the same route and speeds as I usually do. Engine feels noticeably more lively/responsive as well. That is a 10% increase in economy over the previous norm!

I went through the 1957-vintage ECZ 4100 with a fine-toothed comb, but neither it nor the 1957-vintage AFB can touch this edelbrock for drivability or economy it seems. I guess that’s what a few decades of carburetor engineering can do for you.

1954 Crestline Victoria 312 4-bbl, 3-speed overdrive

I have a 450 Quick Fuel on my 292 with a 700R4,I drive it everyday and have put about 30,000 miles on it the last 2 years and it gets anywhere from 15 to 18 mpg 70 mph@ 2100 RPMs

Sorry my mistake. That was 1.6 Tonne for the TBird. 3527 pounds.

That's 3200 lbs. 

When a car here is registered for the first time from another country, it has to go over the weigh bridge.
My TBird came in on the nose at 1.6 Ton with about a 1/4 of a tank of fuel. All cast-iron 312 with auto and porthole top.

I’ve weighed its several times over the years at my local grain elevator and at the drag strip. The 57 Custom 300 I had in the late 60s was about 3600 pounds with a 390 and 3 speed. I’ve found that factory advertised weight is usually less than real world weights.