[Rodney001]

What would be reasonable to expect for miles per gallon for a 289 bored 0.040 over and a somewhat aggressive cam?

I've been driving pretty aggressively but not sure I'm breaking 11-12.

Engine seems happy enough but I would have thought it should do better than that.

Thanks Rodney

 

[rbohm]

my old 289, after it was rebuilt and recamed with the wrong cam for what i wanted the engine to do, turned in 17 city and 25 highway.

 

[happystang]

What kind of transmission? Rear gear? Carb? The 302 in my '66 with a T-5 and 2.79 gears got 30 mpg highway (Jetted fairly lean at cruise)

My '69 with a very aggressive cam, 4 speed, 3.70 gears gets about 9 city and 15-16 highway.

 

[4ocious]

How you drive and the type of roads you drive on have an enormous impact on fuel economy. An ENORMOUS impact. :surprise:

 

[22GT]

OK, I got 18+ in both Pennsylvania and Florida with a 289HP (with 3-2V carbs), wide ratio 4 speed, 3.00:1 rear. The A code 4V I had before that got 21mpg on the highway.

 

[Rodney001]

Carb is edlebrock 1415, top loader 4 speed and I think a 3.26:1 gear ratio not not sure of the last part.


Didn't know if I was driving too hard (likely) or if something needs adjusting.

 

[gt350sr]

So long as I make it to the next gas station without having to push it, I'm happy!! No offense, but if I was worried about gas mileage I'd be driving my wiff's Toyota, not any of my old cars:shrug:

 

[patrickstapler]

^ I can agree with that somewhat. I think for me it's more about is my engine running to its fullest potential and highest efficiency. I'm pretty sure my '66 289 is currently not, but is also not too far off for what I believe to be 336K miles. The best I have recorded this year was roughly 14MPG in town. I haven't really taken any long trips so I can't say what I get OTR. This is after a recent carb rebuild and distributor rebuild/recurve.

 

[zray]

What would be reasonable to expect for miles per gallon for a 289 bored 0.040 over and a somewhat aggressive cam?

I've been driving pretty aggressively but not sure I'm breaking 11-12......."

First your cam is not mpg friendly, secondly, by your own description neither is your driving style. If your are breaking into the double digits, no matter how low, then you have no reason to expect more miles per gallon.

With a stock cam, and driving like there is an unbroken egg on top of the gas pedal, we are fortunate to get above 20 mpg.witth a 50 year old carb'd engine regardless of the rear gearing or transmission. I got 24 mpg once on a long trip and that was a miracle.

Contributing factors:
1) elvation from 4,500 to 9,000' above sea level = thin air & less air resistance.
2) supercharger and carb tuned for very very lean running at low rpm / cruising with an air/fuel meter.
3) 3.00:1 gearing
4)) no traffic
5) more air pressure than normal in tires

Driving the same car "normally" my usual mpg was in the mid to high teens.

OK, I got 18+ in both Pennsylvania and Florida with a 289HP (with 3-2V carbs), wide ratio 4 speed, 3.00:1 rear. The A code 4V I had before that got 21mpg on the highway.

This mirrors my experiences nearly exactly.


Z

 

[HoosierBuddy]

My 2 barrel 289 with a C4 got 10 to 12 MPG.

My EFI 347 has done as well as 28 on the interstate with a 4r70w...put averages more like 24.

Phil

 

[slim]

My Dad had a 58 Olds Super 88 when I was in college. With spirited driving (me) it got about 5 mpg. Dad driving mostly highway...20 mpg. My 63 Pontiac Star Chief is the only car I ever kept track of gas consumption long term. 50,000 miles divided by gallons used equalled a tad over 9. It was a great car, no complaints.

 

[1969sag]

This is a good Question.
Now I am curious what my Fuel Economy is? I have no idea.
I see my gas gauge as a FUN METER. When it gets low, I have to refill the fun meter.
Since I don't use my classics as daily drivers, I just never really cared about it. Maybe I should.
Wonder how burnouts affect gas millage? LOL. Not that I condone that sort of thing.

 

[Rodney001]

Yes spirited driving, that would be me. I guess if the engine is happy, my credit card will just have to get used to it.

 

[289sbf]

I average 11-12 mpg.
289 .30 over-bore, performer intake, hei distributor, very mild cam, dual exhaust, tri-y headers, 3:00 gear, 17 inch wheels.
Fun factor
____________________________________________________________________________________________________________

 

[qbui]

I've been averaging between high 8 to low 11 with my 302 and C4. I don't peel out but I do like to get to my next stop light quickly.

 

[Moodster]

I get about 25 highway and 20 city. Rebuilt .30 over 302 with Edelbrock 2122 cam, ported iron heads, 3-speed and 2.79 gear.

david

 

[stephen_wilson]

OK, I got 18+ in both Pennsylvania and Florida with a 289HP (with 3-2V carbs), wide ratio 4 speed, 3.00:1 rear. The A code 4V I had before that got 21mpg on the highway.

Yup, I got 18-20 with a similar combination in my sig.

 

[2nd 66]

1st 66 was about 15ish mpg ?Cam? 302/3speed 3.00 rear F4B 4to2 barrel adapter Autolite2100 pionts longtube Blackjacks G6014's
2nd 66 low to mid 20's mpg 448/472 cam 289/t-5 .68 overdrive 3.40rear F4B 1406 duraspark triY's 225/50/16

 

[22GT]

My 2 barrel 289 with a C4 got 10 to 12 MPG.

It was broken. That setup should have done 20+ mpg.

 

[Black68coupe]

'68 with 289ci, 500cfm Edelbrock, performer intake, C4, 2.89 gears in 8" housing, headers, 2.25" exhaust, 16" wheels, power steering, 130K miles on original motor (no rebuild):

17 MPG