my bone stock '76 with a 225 1bbl, A833OD, 3.21 gears and 25" tall tires knocks down 19-22mpg city, 25-28mpg highway with a best of 32. a lot of people actually report marginally BETTER mileage after retrofitting the super 6 2bbl setup...
your combo I'd expect about 18-20 city and 22-24 highway.
I'd look at maybe a carb rebuild.
1976 Spinnaker White Plymouth Duster, /6 A833OD
1986 Silver/Twilight Blue Chrysler 5th Ave HotRod **SOLD!***
2011 Toxic Orange Dodge Charger R/T
2017 Grand Cherokee Overland
2014 Jeep Cherokee Latitude (holy crap, my daughter is driving)
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