What kind of mileage is everyone getting?

7173Mustangs.com

Help Support 7173Mustangs.com:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

thunderguns71

Well-known member
Joined
Mar 20, 2013
Messages
85
Reaction score
1
Location
North Carolina
My Car
1971 Fastback small block, now 429.
Took a 330 mile round trip yesterday from my town of Pilot Mountain N.C. down to Chesnee S.C. to see a friend. Hopped in the mustang of course since I drive it everywhere especially since I got the TKO in it and the ole 429 knocked off 18.4 mpg at 70-75 mph. It sure is nice to be able to jump on the interstate and pick any lane I want, lol. Got a lot of thumbs up and surprised looks, especially driving through Charlotte. So what's everyone else getting? Overdriven or not doesn't matter.

 
18 mpg but then I often go over 90 mph on our freeways. Off the freeways it's a lot of curves and narrow roads so you hardly ever get to coast its always accelerate and slow down, accelerate etc which also reduces mpg.

 
when your at cruise on jetting only you get good mileage, throw in a tall rear ratio which lowers RPMs and you gain even more. on a 150 mile trip i took i got over 20mpg.

the minute you hit stop and go traffic you will drop to 8mpg if you are lucky. if you stay off the pedal so the accelerator pump doesn't need to come on much then your mpg will come up.

 
My best tankful was 21 last fall on the way to Tennessee. I averaged 19.5 for the 1600 mile trip.

Around town it's around 12 - 14 depending on routes and traffic.

My goal when all is done would be to average 25 on the highway. I think it's very realistic with a FI engine, overdrive and the proper gearing. Right now with overdrive and a 2.75 gear it luggs the engine too much. 3.25 - 3.50 will get the RPM up from about 1700 to near 2000 @ 70, that should help. Couple that with electric fans. serpentine accessory drive, an 8.8 rear... 25 should be in range.

 
I get around 20-22 highway, and 12-15 city.

these numbers have been very consistent, I have a 302, 2100 carb, FMX transmission, and 2.79 gears (everything is stock)

the only change I have done to the car was replace the stock heads with rebuilt ones that are setup for unleaded gas.

 
I have a 408 Cleveland stroker. c4, 8.8 rear with 373. And on our trip out to Carlisle for the all ford nationals I got around 7mpg. We rejetted the carb and I got a little better up into 9's but around town im always 7-9mpg. Maybe trying out a holley fuel injection setup next year if the money permits and hopefully get into the teens then.

 
What is this 'mpg' that everyone keeps talking about? For my mustnag I like to use the term 'gpm'; gallons per mile:)

 
It improved with the GV. I get about 9 where I was getting about 7. I haven't had the GV on long enough to get a more accurate measurement. And for the last 5 months I have only started it once a month and driven it once at all. But the weather is cooling off so soon it will be mustang time!

 
Around 13-15 for me from a stock fully loaded 2V with AC and pwr everything fmx and 2.75 rear. I think a Aus gallon is 1.2 US gallons,Was a bit shocked by the amount of juice this thing uses for what it is,but hey I didn't buy it because I thought it was going to be economical.

 
Long time since its been on the road but I remember 10-11 on the freeway and 8-9 in the city. That was with 3.25, C6 and 351 Q motor. I'll update when its back on the road again, this time 351 modified, TBI fuel injection, C6 with gear vendor and 3.89 rear. I am thinking city will remain roughly the same but freeway should improve. On the freeway in overdrive the rear will be equivalent to a 3.00 rear. Hopefully better mileage overall.

 
Long time since its been on the road but I remember 10-11 on the freeway and 8-9 in the city. That was with 3.25, C6 and 351 Q motor. I'll update when its back on the road again, this time 351 modified, TBI fuel injection, C6 with gear vendor and 3.89 rear. I am thinking city will remain roughly the same but freeway should improve. On the freeway in overdrive the rear will be equivalent to a 3.00 rear. Hopefully better mileage overall.
I am running the 3.5 gear and the c6. When I put the GV on it my mileage on the freeway went up at least 2mpg and I could drive 75 without all of the noise! It won't pay for itself in gas but the GV gets lots of points for 'smiles per miles'. Going 1st to 1st over is a blast.

 
to paraphrase my grandmother "oh to get 9 mpg . . ." (The actual quote was when she attended a niece's 80th birthday party at the age of 95 and said "Oh to be 80 again)

I'm happy when mileage is 175 miles per tank. At 150 I'm looking for a good gas station.

And since my gas gauge isn't accurate-I have eased into two gas stations this summer with not much more than fumes in the tank.

 
Last edited by a moderator:
to paraphrase my grandmother "oh to get 9 mpg . . ." (The actual quote was when she attended a niece's 80th birthday party at the age of 95 and said "Oh to be 80 again)

I'm happy when mileage is 175 miles per tank. At 150 I'm looking for a good gas station.

And since my gas gauge isn't accurate-I have eased into two gas stations this summer with not much more than fumes in the tank.
Is the gas gauge accuracy due to the fact that you put a new float in it? I don't think mine us accurate too so I am toying with the idea of putting a resister in line to compensate for the float. I know that with a full tank the resistance across the float assembly should be 10 ohms and 73 ohms when empty..

 
Last edited by a moderator:
My stang gets the same around town mileage as my 06 v6 Dodge minivan.

(18 mpg If driven easy!... romping on it 5 mpg)

last March I was 6 mi from home and the fuel pump died. Rather than call a hook

I took the top of the Eldelbrock carb off and filled the float bowl with fuel and made

it all the way home driving as easy as I could...I was rather impressed with 6 mi to

a bowl full!

It depends on how you drive it I bet I could use a gallon on a 1/4 mi WOT pass.

 
I originally got about 10-11 MPG with a bone-stock drivetrain.

Today it gets about 13-15 city, and maybe 16 hiway.

 
Last trip I took to Yosemite with new engine around 18-20.

Around town maybe 10-12.

That's pretty much stock 4V quench Cleveland with some kind

of cam. Also, toploader and 2.75 rear. With the 3.50 ready to be

installed those numbers would likely drop. Forgot to mention the

Holley 770 Avenger.

mike

 
Back
Top