Big Block A body Mileage?

For what it's worth. Back in the 80s I used to get 18mpg with my 273 four barrel, four speed 66 Barracuda and 17mpg with my 68 GTS convertible 340/727. Both cars also had 3.23 gears. The Barracuda had a sure grip.

Fuel changed between 89 and 92 while I had the engine out of the GTS. I never got better than about 14mpg after putting the car back together. The only differences in engines were compression and bore. The old engine was a standard bore 73 short block with 8.5 pistons. The newer engine is a .030 over 10.5 motor. Heads, cam, etc were all the same. The car hasn't been on a long trip in a long time, so I don't know what it would do with today's fuel.