Very impressed with gas mileage

Keep checking it. You'll get your own average over time. Some can rock mpg, others have not a clue. Do you have a vacuum gage? Can you hold the gas pedal steady? Can you coast down hills, use momentum for getting up the next hill? Do you brake coming to a stop? My 64 Barracuda 273 TQ 4 speed would average 25 mpg on a midwest 300 mile stretch between fill ups, odometer dead on. With a 170 slant 6 two barrel high 20's all day long, I'd call it 30mpg on a good 300 mile run. Sounds like you got a good drive train in that car.