decent milege

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fullauto
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decent milege

Post by fullauto »

anybody figure out how to get some decent mpgs out of one of these beasts yet ,i have a 390 in my 250 4x4 was contemplating a swap to a 300 six to see if i could get mpgs up enough to use as a daily driver . would apprecciate any input you guys might have .THANKS,Wade 8)
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Re: decent milege

Post by fmfdoc68 »

Looking forward to seeing some replies on this since my 360 F250 is getting around 8-10 MPG.
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fireguywtc
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Re: decent milege

Post by fireguywtc »

What are you getting now for mileage and what is your idea of decent? There are so many factors that go into mileage but my 70 with a rebuilt 390, 35s mud terrains, and a leveling kit gets 8-10 also. Using ethanol enhanced gas that seems decent to me for my old truck.
Bill
1967 F-250 LWB 2WD 352 V8, 4spd manual, true duals, 122k original miles (currently being restored)
1970 F-250 4x4 highboy ranger 390 V8, 4spd
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68 Ford Stepside
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Re: decent milege

Post by 68 Ford Stepside »

I love my 300 engine, but it sucks on gas mileage. 11 to 12 mpg no matter how or where I drive. I have tried multiple different carbs to no avail. I read a story about the 300 getting 30 mpg with a Carter YF carb, but haven't been able to locate one. :)


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fullauto
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Re: decent milege

Post by fullauto »

fireguywtc wrote:What are you getting now for mileage and what is your idea of decent? There are so many factors that go into mileage but my 70 with a rebuilt 390, 35s mud terrains, and a leveling kit gets 8-10 also. Using ethanol enhanced gas that seems decent to me for my old truck.
well i drive a power stroke van that does 17 around town and about 21 on a trip so anything close to that would be decent to me.don't know what i am geting now because my truck has been sitting in the back yard for over 20 years but when i drove it i could go up a step hill kick in the four barrel and watch the gas guage go down!!! was wondering if anybody has messed with fuell injection or a more modern carb?i talked to clifford performance sometime ago and they claimed 20's were possible out of a 300 with a fuel injection setup and proper tuning.on a side note any of you guys have or seen a 250 4x4 that came with a 300 from the factory?i have owned trucks with 300's but not 4x4 i had a 67 350 dually cab and chassis short bed length truck was awesome!!,Wade 8)
fullauto
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Re: decent milege

Post by fullauto »

68 Ford Stepside wrote:I love my 300 engine, but it sucks on gas mileage. 11 to 12 mpg no matter how or where I drive. I have tried multiple different carbs to no avail. I read a story about the 300 getting 30 mpg with a Carter YF carb, but haven't been able to locate one. :)


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looks pretty interesting,worth looking into,Wade 8)
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Re: decent milege

Post by KnockKnock »

fullauto wrote:
fireguywtc wrote:What are you getting now for mileage and what is your idea of decent? There are so many factors that go into mileage but my 70 with a rebuilt 390, 35s mud terrains, and a leveling kit gets 8-10 also. Using ethanol enhanced gas that seems decent to me for my old truck.
well i drive a power stroke van that does 17 around town and about 21 on a trip so anything close to that would be decent to me.don't know what i am geting now because my truck has been sitting in the back yard for over 20 years but when i drove it i could go up a step hill kick in the four barrel and watch the gas guage go down!!! was wondering if anybody has messed with fuell injection or a more modern carb?i talked to clifford performance sometime ago and they claimed 20's were possible out of a 300 with a fuel injection setup and proper tuning.on a side note any of you guys have or seen a 250 4x4 that came with a 300 from the factory?i have owned trucks with 300's but not 4x4 i had a 67 350 dually cab and chassis short bed length truck was awesome!!,Wade 8)
MegaSuirt is supposed to be the way to go for DIY EFI. If I decide to get fancy I might go this route. Along with better MPG's you can add remote start as well if you like that kinda stuff.

http://www.megasquirt.info/
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colnago
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Re: decent milege

Post by colnago »

With my 352 2WD, I get 10 MPG in-town, and unknown on the highway (last time I took it out, it was suffering ignition problems, so I limped home and didn't really care what kind of mileage I got). I live in a small town, so I only have to fill up every two weeks or so. If it were more often than that, I couldn't afford to use the old girl as a daily driver. I think I have a sticky/burnt/bent intake valve, so maybe I'll get better mileage after rebuilding the heads. But the FE design isn't known for good mileage, so I just sit tall and enjoy the ride. If I stomp on the gas, she'll move, but I tend to keep my foot out of it. I know this isn't what you're looking for, but it's a 50-year-old design, and it just can't keep up with the new engines coming out. Different times, when gas was 29 cents a gallon (probably cheaper when the FE first came out, but 29 cents is the lowest I can remember; $3.93 is the current price in SoCal high desert).

When I got the truck, it came with an Edelbrock 1405 (manual choke) carb on a 4bbl "S" intake (1405 = manual choke and performance; 1406 = electric choke and economy). It got 7.5 MPG in-town, and 9 MPG on the highway. The only thing I have been able to do to give me better mileage was to rejet the Eddy; now I get 10 MPG in-town, and figure that the fifty bucks that the rejet kit cost was money well-spent. I would not have converted from 2BBL to 4BBL myself, but since it was already done, I'm moving forward with it.

Joseph
"Sugar", my 1967 Ford F250 2WD Camper Special, 352FE, Ford iron "T" Intake with 1405 Edelbrock, Duraspark II Ignition, C6 transmission, front disc brake conversion.
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HIO Silver
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Re: decent mileage

Post by HIO Silver »

Three main factors working against more miles per gallon mileage: Engine/drivetrain efficiency, weight, aerodynamics

FE engines are generally inefficient but ... run a 2bbl carb (or EFI like Atomic, E-Street, Powerjection III, or Holley's new Terminator), electronic ignition with a hot spark for a complete burn, headers and a free flowing exhaust system, and port work. Tuning to maximize efficiency and A/F mixture but an EFI system with an O2 sensor can do it for you. Reduce parasitic drivetrain drag caused by wide tires, sticky tires, low tire air pressures, and heavy-bodied lubricants. Change the rear gearing to something more friendly like a 3.00 or 2.79 ratio.

Weight... these things have alot of heavy steel.. it's mostly steel! A dock bumper weighs 75 lbs.. a cast iron intake weight about 70 lbs. Lose or reduce as much as you can. Remove or leave empty auxiliary gas tanks. Compare your rig to modern trucks' plastic interiors and tailgates, aluminum tranny cases and wheels, aluminum suspension components, foam-filled bumpers with plastic fascias, etc.

Aerodynamics... face it. These rigs are like sheets of plywood against oncoming air. ...Seal up body gaps, shave any appendages, install more aero-friendly components like 'sport' mirrors, block off the unused portion of the grill/grill inserts, add an air dam (ever really look under yer truck in relation to on-coming air? There's tons of drag and turbulence-creating parts!), bleed off engine compartment air with a reverse hood scoop or hood vents, , add an undertray, and lower the ride height. In other words, "Slick'er up".

Driving technique and speed is also important. Avoid jackrabbit starts. Anticipate stop signs and traffic signals. Be off-throttle as much as you can. Google search "hypermiling" for additional techniques. Drive no more than 60 mph. It takes significantly more energy (thus HP) as speed is increased... in fact, it's an exponential amount - not linear due to overcoming drag. I suggest researching what HP levels necessary to go 100, 200, and 300 mph at Bonneville.. it's enlightening.

My brother can get 15 hwy mpg with his 360/C6/3.25-geared 1969 F-100. I'm aiming for 20 mpg with my 70 F100... it's an experiment - a very expensive experiment but it's my goal. I've got an E-Street kit already and a TKO-500 should be arriving in the fall.

Lastly, 10 mpg at $4 per gallon is 40 cents per mile. Therefore, do the easiest and cheapest mods for more bang for the buck.
70 F100 LB 2WD, 360FE, E-Street EFI, TKO-500, 76K original miles.. follow my rebuild: The Lo-Buck Bumpside
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73 F100 SB 4WD, 390FE, NP435, +4 on 35s

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KnockKnock
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Re: decent milege

Post by KnockKnock »

A 2-bbl will only get better MPG's than a 4-bbl if the barrels on the 2 are smaller than the primaries on the 4 (and of course you aren't always in the gas & opening the secondaries). It's a common misconception that a big double barrel is better of fuel than a mild four barrel. :2cents:
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hotrodfeguy
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Re: decent milege

Post by hotrodfeguy »

A 390 c-6 can easily pull a 3.00 or even a 2.75 rear gear :2cents:
1972 F-250 4X4 390
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Re: decent milege

Post by elgemcdlf »

You have a 250 4x4. Just what do you expect? I would think about the best you will see short a diesel swap will be 15mpg. You will spend quite a bit of money to get there. Higher gears will probably do the most good for the dollar spent. Your foot will do wonders as well.
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Re: decent milege

Post by ToughOldFord »

I've never gotten more than 9.5 out of my 390. I was close to scoring a deal that would have given me the parts to swap to a 300, but the guy wussed out.

I had a 300 in a '85 F150, never checked the mileage, but it had to be pretty good as I could go between pay checks with a fill up. Never could do that with a FE.

My truck had a 360 when I got it. It was in VERY bad tune. It got 6mpg. Got up to 8 bringing it into tune. The jump to 9.5 was going from C6 to NP435.

FWIW.
1969 F250 Ranger Camper Special. 390, NP435, 3:73s.
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Re: decent milege

Post by Donnie »

HIO Silver makes the a lot of sense (cent's) team..........slick-er up....A bit off topic but still relative.....I've removed the roof rack, installed smaller sport mirrows....extended the cover underneath another foot. It is now about 4 feet long from the front bumper. Run a narrower tire, carry 40 # air pressure & remove the rear seat & all the xtra weight that I could find on my VW jetta diesel & if I drive like an old man, which I am :lol: I can squeak 50 mpg out of this low grade diesel fuel.......There is only so much you can do with the shape & weight of your Bump....But Silver nailed it pretty well :thup:
Use hypermiling....coast down long hills...Install a vacuum gauge & watch it....
Some of you may be old enough to remember the " MOBILGAS ECONOMY RUN'S.....their main instrument was the vacuum gauge...Donnie
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Re: decent milege

Post by mcheath »

My bump has a vacuum gauge, came with the truck. It's pretty cool looking, has a patent date of 1966. I keep my foot out of it, and try to never go below the bottom of the "driving range" when accelerating. Rex drinks so much gas that I can't really afford to feed his habit, so I have to drive it pretty geezerly.

Anyone ever done a propane conversion? I know they get less MPG but propane is about half the price of gasoline here.
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