The Chevy Reaper is a powerful and reliable vehicle, but it’s not known for its fuel efficiency. Depending on the engine size and model year, the average miles per gallon achieved by a Chevy Reaper ranges from 13 MPG to 21 MPG. The smaller 2.7L V6 engine tops out at approximately 17MPG while the larger 6.2L V8 achieves around 14MPG in city driving conditions, slightly better than highway driving conditions with 12MPG estimated. It should be noted that these figures may vary depending on how you drive your particular model of Reaper as well as other external factors like weather or terrain type so it's important to keep an eye on your vehicle's performance over time to get the most accurate indication of fuel efficiency for your specific situation.