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#347032 - 06/14/09 07:23 PM 440 fuel mileage...
minivan Offline
master

Registered: 01/13/04
Posts: 9066
Loc: Eugene, Oregon
So I have run 2 tanks of gas through my 67 stock 375/440 auto... Stock engine, stock cam ,915 heads and the stock AFB that came on the car new.. Everything is rebuilt or new. 294 gears. So far I am getting about 7MPG... Is this normal?? any suggestions as to getting any better MPG.

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#347033 - 06/14/09 07:33 PM Re: 440 fuel mileage... [Re: minivan]
JohnRR Offline
I Win

Registered: 01/20/03
Posts: 73525
Loc: U.S.S.A.
Leave it parked in the garage ?

what convertor ?

I assume your car didn't come stock with 2.94's ?

But that is a little LOW if you ask me but it is a new engine , extra friction till everything seats .

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#347034 - 06/14/09 07:38 PM Re: 440 fuel mileage... [Re: minivan]
buildanother Online   content
I Live Here

Registered: 08/30/05
Posts: 11145
Loc: chicagoland,usa
Highway mpg better get over 10 easily, or somethings wrong.

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#347035 - 06/14/09 07:39 PM Re: 440 fuel mileage... [Re: minivan]
SomeCarGuy Offline
master

Registered: 02/02/03
Posts: 8422
Loc: Someplace you aren't
What is the timing set at? Initial and total

Did you degree the cam in?

Brakes dragging?

The 7 MPG is very low IMO
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Forever in debt to your priceless advice...

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#347036 - 06/14/09 07:45 PM Re: 440 fuel mileage... [Re: SomeCarGuy]
minivan Offline
master

Registered: 01/13/04
Posts: 9066
Loc: Eugene, Oregon
Car came with 3.23 gears

Initial timing 7BTDC

cam was not degreed

Drum brakes adjusted loose..

I was hoping for 10-12....

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#347037 - 06/14/09 07:48 PM Re: 440 fuel mileage... [Re: minivan]
SomeCarGuy Offline
master

Registered: 02/02/03
Posts: 8422
Loc: Someplace you aren't
Try bumping to 12 BTDC.

Are you certain the TDC mark is correct?

10-12 is not hard for a stock setup.

What convertor are you running? Maybe it is too loose for the 2.94 gear.

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#347038 - 06/14/09 09:03 PM Re: 440 fuel mileage... [Re: minivan]
Jerry Offline
master

Registered: 01/20/03
Posts: 6775
Loc: Warren, MI
is the vacuum advance hooked up? how much compression? do you have quench? is the carb jetted correctly? do you have a wideband o2 sensor?
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#347039 - 06/14/09 09:06 PM Re: 440 fuel mileage... [Re: Jerry]
landon1 Offline
mopar

Registered: 06/10/08
Posts: 565
Loc: IA
my 440 was well-worn, but with the WAY too small 600 Holley that was on it, i got about 7 or 8 in town and 10 on the highway....switched to a 650 DP Holley and get about 13...i was hoping with the rebuild, i'd get much better...still hoping, despite your troubles...i'm interested in hearing more
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'71 Satellite Sebring 440

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#347040 - 06/14/09 09:31 PM Re: 440 fuel mileage... [Re: landon1]
DaytonaTurbo Offline


Registered: 02/26/03
Posts: 20826
Loc: Manitoba, Canada
Not sure what my mpg is, but I've got a tired smogger 440 with a thermoquad and I daily drive it everywhere and it's very reasonable on fuel for what it is. I don't complain about its mileage. How heavy is your right foot? I drive mine pretty casually most of the time and mileage is acceptable.

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#347041 - 06/14/09 09:33 PM Re: 440 fuel mileage... [Re: DaytonaTurbo]
landon1 Offline
mopar

Registered: 06/10/08
Posts: 565
Loc: IA
Quote:

Not sure what my mpg is, but I've got a tired smogger 440 with a thermoquad and I daily drive it everywhere and it's very reasonable on fuel for what it is. I don't complain about its mileage. How heavy is your right foot? I drive mine pretty casually most of the time and mileage is acceptable.





pretty heavy foot somedays
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'71 Satellite Sebring 440

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#347042 - 06/14/09 09:46 PM Re: 440 fuel mileage... [Re: minivan]
Doc Fiberglass Offline


Registered: 07/04/08
Posts: 17475
In my 62 Belvedere .... stock and worn-out 440 with a 509 cam.... TQ with a SD intake and iron exh mans and a 2.76 gear ... got 17 mpg ....

....and ran bottom 12's ...at 100 mph or so.(BAD speed for that ET because of poor ring seal).

Something REALLY is wrong with your FRESH combo. I would check the primary jetting on that carb. It has to be way WAY fat.

Suggestions? .... a Plastic Fantastic ...aka ThermoQuad.

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#347043 - 06/14/09 10:28 PM Re: 440 fuel mileage... [Re: landon1]
dave571 Offline
master

Registered: 12/02/03
Posts: 5314
Loc: Carstairs, Alberta, Canada
still a stock cam in there?

I think I would look at the distributor. could have seized weights. Should do better than that with that combo.

I bet I got close to 20 mpCDNg in my stock cammed 383 2bbl 68 newport.(16 mpusg or so)

I would think 12-15 would be a reasonable expectation if the foot is lightened
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#347044 - 06/14/09 10:44 PM Re: 440 fuel mileage... [Re: dave571]
Dusted_Ya Offline
super stock

Registered: 01/22/03
Posts: 855
Loc: The Dalles, OR.
78 Powerwagon with 32" mud tires, 4:10 gears and I'm getting 8.5mpg on the highway. Either you are not getting any timing advance or your carb is somehow causing a very rich environment. Pull a couple of plugs and smell them/inspect for rich condition

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#347045 - 06/14/09 10:59 PM Re: 440 fuel mileage... [Re: Dusted_Ya]
Robbins Offline


Registered: 05/03/04
Posts: 4899
Loc: Joplin, MO USA
My buddy's 74 factor 440 truck with 3.55's, 3/4 ton gets 14 on the highway. Unloaded........of course.
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#347046 - 06/14/09 11:31 PM Re: 440 fuel mileage... [Re: Robbins]
minivan Offline
master

Registered: 01/13/04
Posts: 9066
Loc: Eugene, Oregon
Brand new plug an play pertronix distributor.. I have not checked it for total advance yet.. The original, rebuilt, AFB is on the car. I forget its number but it is correct for a 67 auto 375/440.. I want to assume its jetted as it was from the factory.. I think the car is rich and will check jetting and timing..

Wanted to have car running by May 30th, so I need to go back and fine tune somethings.. My question was "is this kinda crummy MPG" for a 440...

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#347047 - 06/14/09 11:34 PM Re: 440 fuel mileage... [Re: Jerry]
minivan Offline
master

Registered: 01/13/04
Posts: 9066
Loc: Eugene, Oregon
Yes vacuum advance to the port on the carb.

low stall torque converter..

9.2-9.3 compression..

915 heads..

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#347048 - 06/14/09 11:59 PM Re: 440 fuel mileage... [Re: minivan]
BIG-MIKE-500 ci Offline
member

Registered: 09/09/08
Posts: 42
Loc: Nelson-New Zealand
Well rick, I have an Aussie Charger with a stroker 440(500 ci)with comp cams 294 solid(248@050)Wiend Xcelerator single-plane,Stealth Heads,650 D/Pumper Holley(YES,650)10:1 comp 193 lbs cranking pressure,factory dizzy set at 36 degrees total with 22 initial advance.MSD 6AL ignition.
I run a 4-speed new-process with 2:75 gears out back with 25 inch diameter wheels.
This car weighs over 4100 lbs with me & fuel & it runs 12:00 @ 118 mph & does 17 mpg Imperial which I guess is about 15 US to the gallon.
Now I use all the throttle when I accelerate wherever I can & cruise about 70-90 mph.
Would suggest you get your total timing right & then get your initial set after that. Not hard to do.
If thats alright get into that damn carbby; something is very wrong.
cheers, Mike.

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#347049 - 06/15/09 02:56 AM Re: 440 fuel mileage... [Re: BIG-MIKE-500 ci]
Pale_Roader Offline
master

Registered: 01/21/05
Posts: 4339
Loc: the frozen wastes...
Personally, i think 440's just suck in this dept. compared to other makes. I haven't owned them all, but i've had a few 440's, some were nice runners, good tune and car etc. They all got [Edited by Moparts - Keep it clean] mileage. My Charger with its stock 76 440, full (very nice) exhaust, elect. ign, de-optioned (as in no power anything) and no air cleaner even gets around 8MPG. Thats with 3.23 gears and i know how to drive for mileage.

I've never had a 440 in anything that could touch my 68 Cadillac's mileage, and thats a high-comp 472 in a 6000lb car with all kinds ov problems.

I blame the lack ov quench more than anything. My Caddy has it, my Charger (and other Mopars) never had it. Mopars just aren't efficient from the factory in my opinion. You need to rebuild them and buy some real pistons.

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#347050 - 06/15/09 03:13 AM Re: 440 fuel mileage... [Re: Pale_Roader]
Pale_Roader Offline
master

Registered: 01/21/05
Posts: 4339
Loc: the frozen wastes...
Ideas for better mileage? First and foremost, hows your driving? I know everyone is the best driver in the world, but the difference between two different drivers in mileage can be vast. Lets assume you know how to squeeze the most from a tank.

Exhaust, probably the biggest improvement i've seen (other than fixing something that wasn't working right) was with exhaust. Headers, 2 1/2" (MINIMUM) or 3" mandrel pipe, X-pipe, high flow mufflers. Theres a LOT there over a stock style system.

Distributor recurve, putting a good tune into the distributor is a nice improvement over the stock tune.

Friction in the driveline, vibrations cost power/mileage, as do improperly inflated tires.

Hotter/better spark, MSD ignition? I haven't done this yet, but from all accounts, this is a nice improvement over stock as well.

Intake, maybe a weird suggestion, but everything improved when i put a Street Dominator on my 440. Went up eight jet sizes and still ended up with better mileage. That stock intake really does suck.

Better carb? Again, i dont know about this first hand (i always use Holleys) but everyone tells me that Thermoquad is magic... IF it works the way its supposed to. I DO know that a Q-jet is superior to a Holley, so i would think a plastic Thermo would be as good or better?

Use the LOWEST stall converter you can get away with....???

Put a serious shift kit in the tranny.

Synthetic fluids from front to back. You'll be out over $100, but this made a seat-o-the-pants difference in my 96 Mustang GT, and those cars already get wicked mileage.

And my personal favorite (after the exhaust)... weight reduction. Put 'er on a diet.

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#347051 - 06/15/09 06:15 AM Re: 440 fuel mileage... [Re: minivan]
JimG Offline
mopar

Registered: 07/17/07
Posts: 529
Loc: Virginia
My sig car was bone stock except for MP electronic ignition when I bought it in 1981, and it got waaaaay better than 10 on the highway, around 14+. I drove it to Myrtle Beach from Virginia in 1982 and I remember it wasn't terrible.

My compression ratio was advertised as being higher that yours, although I didn't measure how far down the pistons were in the hole when I built the motor the first time in 1984. Ah, the indescretions of youth!

You've got some good suggestions so far. I assume you have a stock cam since you're running the stock AFB? Those carbs were calibrated very well for the stock engine, and should give razor-sharp performance and decent mileage if everything is as it should be. You might want to get an O2 bung welded into your exhaust somewhere and pay someone with a wideband meter to give it a look-see to be sure the factory calibration is still intact. Someone may have changed jets, metering rods, springs, etc. I still have my original AFB disassembled in a box - if necessary I can tell you which rods and jets it has. Springs might be more difficult to identify.

With a dialback timing light or with a timing tape installed, be sure the advance curve looks good, and be sure the vacuum advance is working right. The spring tension on the vacuum advance is adjustable if you're running a stock distributor or the MP unit - if you don't know how to adjust it one of us will explain it if you're interested.
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