I'm going to try a Holley Street Dominator and an electric choke (800 ThermoQuad). I'm good as long as it works ok and makes a lot of noise. On my stock 273-2bbl Dart. Anytime I drive any of my cars that have a Thermoquad, I have to hear it just once!
So-is the 273 in a 69 or earlier car with the cast iron water pump? If so, all above suggestions are for the 70 up aluminum setups, everything is different. Vintage Air has a kit for the 69 and down, part number 161004.
The 440-3.23 B bodiies were top enders in my neck of the woods. These were about the only cars that we would outrun the State Patrol in. In 1970 the county I lived in-the County Sheriff and 3 or 4 Deputies drove 70 Charger R/T's and Coronet R/T's, all with 440 and 3.23 gears. I once heard...
You said freway driving, that means 2.76. My 67 Dart 273 2bbl 2.71 gears, 225-70-15 rear tires. Get 20-21 mpg. A big help would be the A&A Transmission part throttle kickdown kit, it helps drivability a bunch.
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