How many miles per gallon should you get with your 1983 cutlass supreme a 307 engine?

The fuel economy of a 1983 Oldsmobile Cutlass Supreme with a 307 cubic inch engine varied quite a bit depending on several factors: the car's condition (tune-up, tire pressure, etc.), driving habits (aggressive acceleration vs. gentle), and the type of driving (city vs. highway).

However, a reasonable expectation for highway driving would be in the 18-22 mpg range. For city driving, expect something closer to 14-18 mpg, or possibly even lower depending on the conditions.

Keep in mind that these are just estimates. An exceptionally well-maintained car might exceed these numbers, while a poorly maintained car could fall significantly below. Your actual mileage may vary.