[71 T/A]

I remember reading how a 73 Trans Am had an EPA Fuel Estimate on its sticker of 8.
I was wondering what's the lowest mileage you had for a car you owned or currently owned?
As I was contemplating doing a 535 for my 69 GTO and was thinking how a motor like that is likely good for 5-6 mpg, was just thinking out loud.

[Formulajones]

Alot of the original EPA mileage figures on these cars were given with factory crappy tunes that had emissions in mind more than economy so I take all that with a grain of salt.

Worst I've had is about 10 mpg out of a 600 HP 454 that I currently drive, with 4.10's and no overdrive. That's after alot of wideband tuning in the part throttle areas to achieve that, and normal driving.

Bigger cubes get pretty thirsty though. My fathers 571 he's driving on the street with over 700HP, he's reporting about 5 mpg with 3.73's and no overdrive. But the tuning is fresh off the dyno with no part throttle tweaking as of yet. I feel there might be 1-2 mpg in it but it's going to be tough on fuel either way. Converter needs tightened, and may drop the rear gear to 3.50'ish when the rearend is done again.

The fun factor far outweighs the fuel mileage, and building these engines to run on pump gas is what makes them affordable to drive.

[snake charmer]

A 1990 Ford F250 with a 460, was getting 5-6 mpg.

[Formulajones]

LOL, Sometimes I wonder how some of that stuff could be that bad.

My current 79 1 ton 454/400 turbo with 3.73's gets 14 mpg, and with it's current 502 crate motor it's getting 11-12 mpg around town.

[A.W.Dille]

My Chevy pick-up gets around 10 on a good day. Averages around 8 normal driving. My GTO only got around 7-8 when I was running the Holley, gets around 12 with the present Q-jet. GP has gotten about 18 on a long drive.

[72projectbird]

94 F350 351w on 35's gets around 9mpg. Good thing both tanks work!

[scld1354]

Originally Posted by 72projectbird

94 F350 351w on 35's gets around 9mpg. Good thing both tanks work!

'93 Bronco w/ a 5.8 (351), E4OD, 3.55s with 30" tires got around 12mpg unloaded, got 9mpg from CO to CA towing a 65 GP.

[72projectbird]

Originally Posted by scld1354

'93 Bronco w/ a 5.8 (351), E4OD, 3.55s with 30" tires got around 12mpg unloaded, got 9mpg from CO to CA towing a 65 GP.

That GP is a big car to be pulling around

Once the snow starts flying and I have the blade on it the mpg's go out the window.

[Kenth]

My 1970 Judge 455 .030" 744 cam TH400 3.55:1 225/70x14 got 10.5 - 12.3mpg

My 1966 Tripower 400 .030" 068 cam TH400 3.07 215/75x14 got around 16mpg.

[jonmachota78]

Originally Posted by 71 T/A

I remember reading how a 73 Trans Am had an EPA Fuel Estimate on its sticker of 8.
I was wondering what's the lowest mileage you had for a car you owned or currently owned?
As I was contemplating doing a 535 for my 69 GTO and was thinking how a motor like that is likely good for 5-6 mpg, was just thinking out loud.

Those low comression motors were not efficient, hence the bad milage. With the parts available today you can build a more efficient and powerfull motor with big cubes. Have your cake and eat it.

[Tom Vaught]

Originally Posted by jonmachota78

Those low comression motors were not efficient, hence the bad milage. With the parts available today you can build a more efficient and powerfull motor with big cubes. Have your cake and eat it.

X2

Did the Emissions and F.E. side of the business for several years. The old EGR stuff and other add-ons were basically band-aids until the Research People and Automakers could come up with proper systems.

Then: 78 Trans Am (11 City and 15 Highway) was the best for me but the engine was untouched with all of the stuff still on it.

64 GTO Tri-power actually got better mileage (but was lighter too).

Tom V.

[Keith Seymore]

My GTO (389, tripower, 4 speed, 4.88:1 gears) gets about 4 mpg.

My Chevelle (555 cu in, approx 900 HP naturally aspirated) takes about one gallon of Torco 110 per 1/4 mile pass.

K

[66bonne]

Originally Posted by Keith Seymore

My GTO (389, tripower, 4 speed, 4.88:1 gears) gets about 4 mpg.

My Chevelle (555 cu in, approx 900 HP naturally aspirated) takes about one gallon of Torco 110 per 1/4 mile pass.

K

Keith: 1 mpg is about what I get with my 495 Poncho motor in a 4,000 pound Catalina.
Jim

[Big Mike]

I'd say my drag racing car. 4 gallons to the mile........

My one ton Dodge van is heaven compared @ 10 MPG on a good day.

Race car $12.00 gallon - Work van $2.85 a gallon!

[RocktimusPryme]

I drove a Uhaul box truck towing my car on a trailer from Tampa to California. Averaged about 7.8 mpg. That was an expensive move...

[David Jones]

Mom had a 72 Country Squire wagon with a 400 2 barrel back in the day. The word combo "gas hog" was created for it.

[hurryinhoosier62]

Originally Posted by David Jones

Mom had a 72 Country Squire wagon with a 400 2 barrel back in the day. The word combo "gas hog" was created for it.

Didn't pass many gas stations, did it? Dad's '66 Country Squire with a 390/4bbl/3.70 gears(towing package) got 8-10 mpg. The worse one I've ever drove was a friend's 289 Cobra. If I recall, Chris said it got around 6 mpg.

[dataway]

78 Chevy full size PU, 350 4bbl auto, original engine. Would get 12mpg highway, city, 80mph, 30 mph, empty, full, uphill, downhill. You could throw it out of a plane and it would still get 12mpg.
It defied everything I learned about physics and the conservation of energy.

JohnnyB

[David Jones]

Originally Posted by dataway

78 Chevy full size PU, 350 4bbl auto, original engine. Would get 12mpg highway, city, 80mph, 30 mph, empty, full, uphill, downhill. You could throw it out of a plane and it would still get 12mpg.
It defied everything I learned about physics and the conservation of energy.

JohnnyB

[Matt Meaney]

Originally Posted by dataway

78 Chevy full size PU, 350 4bbl auto, original engine. Would get 12mpg highway, city, 80mph, 30 mph, empty, full, uphill, downhill. You could throw it out of a plane and it would still get 12mpg.
It defied everything I learned about physics and the conservation of energy.

JohnnyB

yup, everything you said for a '72 K20 350 4bbl original engine auto with 4.10's, except it was 10mpg.