In town mileage is hurt, cause we are trying to get 4000 ids up to speed, on the highway, it rolling resistance, AND wind resistance. Usually, less filling of each cylinder per mile is the answer, if everything is set up right. If our engines were turbo charged, then lowering the RPM, and increasing the manifold pressure would do the trick. Read what Charles Lindberg did during WWII to help the P-38 guys save fuel. Two cents.
