What kind of gas mileage can I expect when my challenger is done?

[charlie challenger]

It has a 440 with 355 gears.  It should be ready to go this spring.  Thank God I don't need the higher octane gas! 

[71bigblock]

I think that there are too many variables, do you have some more drivetrain information? 

If it is pretty much stock, and you drive like your grandma, 15 tops.  Most likely quite a bit less than that. 

[ntstlgl1970]

I think that there are too many variables, do you have some more drivetrain information? 

If it is pretty much stock, and you drive like your grandma, 15 tops.  Most likely quite a bit less than that. 

I'd agree, best I ever got was 16-17 on the highway with the stock motor, headers and 2.76 gears. Really have to keep your foot out of it though...

[73Chally]

I'd agree, best I ever got was 16-17 on the highway with the stock motor, headers and 2.76 gears. Really have to keep your foot out of it though...

   I guess the good thing about using the 87 octane gas is that you have to keep your foot out of it, or else you will detonate out the wazoo.

[charlie challenger]

I have a 3 speed auto 727. 
What would happen if I put a higher octane fuel in my car?  Would I see a difference in performance?  Would it run harder, faster, use more gas, or would I not notice a difference.  My compression ratio is around 9 to 1. 

[HP2]

I'm going to say 10-12, tops. Will probably average around 7-8 since a 440 Challenger is not exactly a grannie car. The compression isn't so high to improve efficiency a great amount, and it probably has a bigger than stock cam, which will probably be a less efficient combination than stock.

Running higher octane gas than your engine needs does nothing to provide more power. All you would notic eis your wallet draining faster. Power comes from the combination of mechanical parts in your engine. Octane allows you to running a more powerful combination of parts. If you haven't built it with those parts to begin with, then changing the octane will not provide more power.

[73Chally]

My bad.  I'm running a 440-6 with 10.5:1, and tried 87 once just to see what would happen, and needless to say I never did it again.  The internals have a lot to do with the mileage.  My brother-in-law gets about 7MPG with a 383, but it has a monster cam.  I would think a mild cam and moderate compression should get low to mid teens.

[RabidScott]

Mileage is always going to be bad with a big block Chrysler.  You could grandma it around, but then you may as well have a slant six, because you don't run 440 for mileage purposes.   

I usually got somewhere between 6 and 9 mpg with a 850 mechanical secondary carb, four speed, 3.91 LSD, and a heavy right foot.   

[BIGSHCLUNK]

 milage....       

[71bigblock]

Mileage is always going to be bad with a big block Chrysler. 

Not necessarily true, I average about 16 mpg with my 383 2 bbl.  Better than my Ram used to get.   

[MEK-Dangerfield]

It has a 440 with 355 gears.  It should be ready to go this spring.  Thank God I don't need the higher octane gas! 

Is the engine built to stock specs, or do you have a bigger cam and after-market intake? What size carb do you have? How do you plan to drive it? With 3:55's, I really can't see you getting more than 10-12 MPG with the little info you have provided.


  Mike

[nivvy]

I get 2   

[moparmaniac59]

It's a Mopar, It's a Muscle car, It's fast, It's loud, It's a big block (V-8 no doubt), It's from the 70's. It's a honking big 4 barrel, Headers, Duel exhaust, Pedal to the metal!!!  MPG's, who cares? Any questions?? Just kiddin....I get about 10 MPG (average driving) with my 440 and interstate gearing (3:23) and automatic.


                                                             Matt B.

[MEK-Dangerfield]

In all honesty, I can get 13.3 on the hiway with a 440 and 3:23's at 65-70MPH. I got a big cam, Holley 800 carb, ported heads, headers...blah, blah, blah. I attribute this somewhat to connecting the vacuum advance. I'm REALLY proud of that.        I know others get much less.   


   Mike

I doubt this is because I'm a good mechanic.   

[ted]

my rt has a 440 with 3.55 gears and gets 11 mpg