Re: 440 fuel mileage...
[Re: minivan]
#347035
06/14/09 09:39 PM
06/14/09 09:39 PM
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Joined: Feb 2003
Posts: 10,218 Someplace you aren't
SomeCarGuy
I Live Here
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I Live Here
Joined: Feb 2003
Posts: 10,218
Someplace you aren't
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What is the timing set at? Initial and total
Did you degree the cam in?
Brakes dragging?
The 7 MPG is very low IMO
I want my fair share
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Re: 440 fuel mileage...
[Re: Jerry]
#347039
06/14/09 11:06 PM
06/14/09 11:06 PM
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Joined: Jun 2008
Posts: 565 IA
landon1
mopar
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mopar
Joined: Jun 2008
Posts: 565
IA
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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
'71 Satellite Sebring 440
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Re: 440 fuel mileage...
[Re: landon1]
#347043
06/15/09 12:28 AM
06/15/09 12:28 AM
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Joined: Dec 2003
Posts: 5,314 Carstairs, Alberta, Canada
dave571
master
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master
Joined: Dec 2003
Posts: 5,314
Carstairs, Alberta, Canada
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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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Re: 440 fuel mileage...
[Re: Dusted_Ya]
#347045
06/15/09 12:59 AM
06/15/09 12:59 AM
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Joined: May 2004
Posts: 4,920 Joplin, MO USA
Robbins
master
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master
Joined: May 2004
Posts: 4,920
Joplin, MO USA
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My buddy's 74 factor 440 truck with 3.55's, 3/4 ton gets 14 on the highway. Unloaded........of course.
Moparlee
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Re: 440 fuel mileage...
[Re: BIG-MIKE-500 ci]
#347049
06/15/09 04:56 AM
06/15/09 04:56 AM
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Joined: Jan 2005
Posts: 4,862 the frozen wastes...
Pale_Roader
Swears too much
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Swears too much
Joined: Jan 2005
Posts: 4,862
the frozen wastes...
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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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Re: 440 fuel mileage...
[Re: Pale_Roader]
#347050
06/15/09 05:13 AM
06/15/09 05:13 AM
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Joined: Jan 2005
Posts: 4,862 the frozen wastes...
Pale_Roader
Swears too much
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Swears too much
Joined: Jan 2005
Posts: 4,862
the frozen wastes...
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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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Re: 440 fuel mileage...
[Re: minivan]
#347051
06/15/09 08:15 AM
06/15/09 08:15 AM
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Joined: Jul 2007
Posts: 531 Virginia
JimG
mopar
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mopar
Joined: Jul 2007
Posts: 531
Virginia
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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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