74 Dart. Headers vs manifold.

In town mileage is hard to increase, with billions of dollars in research over the last 4 decades from manufacturers . Cars similar to our A Bodies don't produce all that much more mpg then we got. We get mid teens they get mid-high teens depending on the car. My jeep gets low teens.

I spent $5000 on efi/ignition at best I may gain a couple mpg. And I plan on this car car to be 9 months out the year daily driver but it probably would take 15 plus years to recoupe that cost. My main goal is driveability then performance with and eye on mileage.

Highway mileage you can gt decent increase and if do enough driving could recoupe in 5 or so years. But all in all if mileage is your primary reason for mods its cheaper to dump it into the tank. A gain of 3 mpg is only like saving around $300 a year.