75/76 Dodge Dart /6 average MPG and improvements

I would stick with the one barrel carb and do a couple Hot Rodder tricks. A header with 2 1/4 exhaust and a better air cleaner set up will help. Research light weight wheels. They reduce unsprung weight which saves gas and adds to power. Look for ways to reduce weight from the car. And of course tune it really good. I would also look for a A-body without power steering and A/C. Less problems- better mileage. Just my opinion, based on my experience