Daughter needs Gas mileage from 273 commando
Yes, that's how I learned to drive "economically". I had a few 67/68 Barracudas in my day. I installed a vacuum gauge in the dash and used that to drive with maximum vacuum to get better economy.
I also had an '85 Laser XT brand new with the navigational computer that had a button to monitor current fuel economy. That also helped me learn to drive economically. I liked to get it up to 70 or more on the highway and put the clutch in and coast, then watch the economy meter max out at 99 MPG! It was a fun game.... I used to be able to get 32-34 MPG on the highway with it, and about 26 MPG city.
But it's easy to put in a vacuum gauge and tell her to try to drive with as much vacuum as possible.