Mileage by Brand and Octane for My 1967 Mustang

Gas Mileage

Here's some interesting trivia about gas mileage. Have you ever wondered which brand, grade, or octane rating gives better gas mileage? Well, I've collected thousands of miles of data on a wide variety of brands, octane ratings, grades, etc. All this information is from my 1967 Ford Mustang. I have found these results interesting, I hope you do as well.


Octane Rating by Brand

So, the first question I got from someone when I showed these gas mileage calculations off, was "What about octane of specific brands - that would probably be more useful." So, here it is... Gas mileage results from my records for different brands at specific octane ratings.

Only combinations that have been recorded more than 10 times are listed to try to eliminate deviant results.

BrandRatingNumber of EntriesAverage MPG
Cennex 85.5 29 13.86
Cennex 87 11 14.66
Cennex 88 17 20.55
Conoco 85.5 40 18.42
Conoco 88 15 18.14
Exxon 85.5 20 15.94
Exxon 87 18 17.19
Exxon 88 11 17.55
Holiday 88 12 17.64

I, of course, make no guarantees about what kind of gas mileage you may receive in your vehicle, even if it is a '67 Mustang with an L200 and a couple hundred thousand miles under the hood, because there are way too many variables that come into play...