383 gas Mileage

[NCMark]

I have a 63 Sport Fury with a 10.3:1 compession 440. 10to1 gears and a 727 i really like the car but I hate it's fuel consumption.
:angry1: todays gas prices take the fun out driving.
I'm considering a 383 fourbarrel and some taller gears what kind of milage can I expect.


mark in NC

 

[ODZKing]

Mine is a 67 383 4bbl. It's a 2.94 rear w/o sure grip.
On trips depending on using good gas or not I can get 17-18.
Around town maybe 12 IF I stay out of it. I originally was disapointed to find when I bout it that it only had 2.94's. But I cam to the realization I will NEVER race it and it was better for milage so I have quite pleased and other than and EI conversion it is pretty much stock.

 

[terzmo]

That 383 is not going to do any better than the 440. It's driving habit and gears. I had a 498 stroker with 355's and got 12 around town, staying out of it with a 950 proform carb. I currently have a mild 440 with an old edelbrock,750 and get about the same with 391's. I don't believe spending the money to change to a 383 is cost effective, even in the long....long....long...run....plus it decreases re-sale price. (440 is more attractive than 383) If you don't care about sluggish performance off the line....go to 276's. I hate paying for fuel but the warm weather here is not like the south so I chalk it up to entertainment and drive the heck out of mine. I don't care what the gas price is.

 

[Badvert65]

When I had a 383 4 bbl (Holley 600), automatic and 3.23 gears I was getting about 15 mpg on the highway. That was driving around 70 or so, not being careful. Not bad for a big 65 Fury (C body).

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What gears are you running now? It would be easier to try a lower (numerically) gear set before swapping engines.

 

[Coyoteduster]

Don't pull that trigger! Terzmo is spot on, you can accomplish the same thing by adjusting your driving habits and not have to give up your 440, but there's only so much you can do. I have a 10.5:1 383 with a 650cfm AFB, w/391 sure-grip and a 4 speed that gets 12mpg city, tops! Fuel consumption is the price that you enjoy for the privilege of driving a classic big block Mopar muscle car. ;)

 

[NCMark]

So my best bet is is to go with a 3:23 gear set, i have 4:10. I may have to take it to the local drag strip before I do the change out.. I have a holley 800 double pumper that's running a little rich, I could install some leaner jets also

Thank you all or y'all

Don't pull that trigger! Terzmo is spot on, you can accomplish the same thing by adjusting your driving habits and not have to give up your 440, but there's only so much you can do. I have a 10.5:1 383 with a 650cfm AFB, w/391 sure-grip and a 4 speed that gets 12mpg city, tops! Fuel consumption is the price that you enjoy for the privilege of driving a classic big block Mopar muscle car. ;)

 

[Meep-Meep]

I'm one for squeezing out as much fuel economy as possible and within reason. I also like to use that as a tuning reference, meaning, if I was getting 8 MPG out of a mild 440, and it was not in a motor home, something be wrong! So really this says there should be a proper amount of fuel consumption based on the HP output. We had a guy on here that was proud to be getting 4 MPG out of his hot street driven 440 and I thought that was way to much fuel for going down the road. And all that fuel is doing major damage to his engine (assuming he's not at WOT at max HP).

I'll agree that going form one big block to another will be little gain vs. the effort. Look carefully at your current build and make adjustments. If you have a big cam then forget about any gas mileage efforts. At that point you will want to put a bigger LSA cam in 112 - 114 with a miler profile to get your torque peak in the RPM range where you drive. This may also require you to drop the compression to 9.5:1. Also the 2.94 gears will help a lot.

 

[coloradodave]

4:10 gears and a Holley 800 Double pumper are major mileage killers. If mileage becomes your priority try a set of higher gears and a 600 CFM vacuum secondary carburetor. I'd look for good used parts as buying new will take a LONG time to get a return on your money. Good luck.

 

[63RedFury]

You need to get rid of it and buy a slant 6 car.I happen to have a slant 6 duster I would trade you......LOL

 

[paladin06]

I never can understand why anyone looks at the gas mileage on a muscle car. I always thought gas mileage concerns were for tree huggers.
JMVHO

 

[Coyoteduster]

So my best bet is is to go with a 3:23 gear set, i have 4:10. I may have to take it to the local drag strip before I do the change out.. I have a holley 800 double pumper that's running a little rich, I could install some leaner jets also

Thank you all or y'all

The 323's alone will make a noticeable difference and anything you can do with that rich running carb will help. What kind of mileage are you getting now?

 

[Badvert65]

The name "Double Pumper" should tell you something about that carb. Don't get me wrong, I like Holley Carbs, but if mileage is a concern, then definitely go with Vacuum secondaries.

 

[Dodge 330]

No reason why a 440 with 3.23 gears shouldn't get 14-15 mpg but thats going to be about the best.

My 440 with 750 3310 (vacuum secondaries) would do that at 70mph on the highway. Headers, .528 Mech. cam but otherwise bone stock and 9.5:1 CR.

 

[Mark B]

I've got a 78 Ramcharger 4wd with front lockouts sporting a 70 vintage 440 magnum with the stock truck 4 speed trans and cheap headers it was getting 12-14 mpg on the highway. The 400 2 barrel and iron manifolds only got 8-10 mpg tops. So it's not all about engine size.

 

[red 69 runner]

X2

I never can understand why anyone looks at the gas mileage on a muscle car. I always thought gas mileage concerns were for tree huggers.
JMVHO

 

[Gone]

Nobody's in this game for better fuel mileage. If your engine is properly tuned, the fuel mileage is what it is.

 

[A383Wing]

if you want gas mileage...buy a Prius

 

[coronet340]

I used to have a 318 with a 4bbl. Around town I would get close to 8mpg. Highway a sweet 6mpg. Enjoy your double digit mpg's because it could be worse!! lol

 

[Centerline]

4:10 gears and a Holley 800 Double pumper are major mileage killers. If mileage becomes your priority try a set of higher gears and a 600 CFM vacuum secondary carburetor. I'd look for good used parts as buying new will take a LONG time to get a return on your money. Good luck.

I agree completely. This will make a world of difference.

 

[furyrestored]

big block mopars and fuel mileage shouldn't be used in the same thread it is what it is