What's the absolute maximum range of your Duster?
See your /6 Duster has a 7 1/4 rear end.
Lots of those came with 2.76 ratio. Had a 74 /6 Dart Swinger that came 2.76, automatic.
A little taller rear tire will give you actual more miles per gallon.
Kind of doubt you have a 3.23 ratio, but you can check. 2.76 rear gears will be best for mileage if that is your main concern.
Would think you could be closer to 20 mpg if set up right with that /6.
Had a '69 Satellite with stock 318, 4bbl upgrade, 727, and 2.94 rear gears. That one got 20 mpg. Everything was set up right working well together.
9.2:1 compression ratio in '69 helped too, more power out of the same fuel.
☆☆☆
See your /6 Duster has a 7 1/4 rear end.
Lots of those came with 2.76 ratio. Had a 74 /6 Dart Swinger that came 2.76, automatic.
A little taller rear tire will give you actual more miles per gallon.
Kind of doubt you have a 3.23 ratio, but you can check. 2.76 rear gears will be best for mileage if that is your main concern.
Would think you could be closer to 20 mpg if set up right with that /6.
Had a '69 Satellite with stock 318, 4bbl upgrade, 727, and 2.94 rear gears. That one got 20 mpg. Everything was set up right working well together.
9.2:1 compression ratio in '69 helped too, more power out of the same fuel.
☆☆☆
