383 sixpack 6mpg???

[Cratos]

I have about 500 mile on my 383 sixpack  purple came ( six pack cam) 355 rear 295-50-15 tires 727 auto
center carb 62 jets outboard 82  brown springs in out boards
running 10-12 on the AFR
only getting 6 mpg!!!
Help

[Chryco Psycho]

wear lighter shoes !!

[worthywads]

295s are a big drag on the rolling resistance.  How accurate is your odometer?

How far are you driving?  A lot of stop and go and having fun is gonna be bad.  Have you driven 100 miles at 65 for a better gauge of highway miles?

Are you driving with windows down and no back window?  That is killing what little aerodynamics you have.

[Chryco Psycho]

stop & go is always bad , where is the timing ?
10-12 on the AFR is  rich for sure , , float levels set ?
you could drop to 58-60 on the main jets , Plug color ?

[Cratos]

mostly around town driving  taking it easy during brake in, timing is around 10 btdc vacuum about 15
I have not pulled the plugs yet. acording to the local radar sign speedo is very close +1

[Chryco Psycho]

I would put initial timing up to 15* & reduce or disconnect the vacuum advance
Make sure he float level is right & then look at jetting it down
mileage will be down while the engine is breaking in also

[worthywads]

mostly around town driving  taking it easy during brake in, timing is around 10 btdc vacuum about 15
I have not pulled the plugs yet. acording to the local radar sign speedo is very close +1

Keep in mind the speed and odometer are not directly related, my odometer is pretty much dead on but me speedometer reads 71 when i'm going 65.  I use the mileage markers and did a 10 mile drive.  Probably not going to be way of but you could be 5-10% off.

[JS29]

@Chryco Psycho  Is right, fresh engines are full of friction. They will run hotter and use more fuel.   

[73_Cuda_4_Me]

At it's best, the one that got away from me - 69 roadrunner 440-6, 4-speed, 4.10 Dana - got 8 mpg...

Gawd I wish I had that one back!

[usraptor]

Download a speed app on your phone and then check your speed on the phone vs your speedo.  When my speedo says 70 MPH the app says I'm actually going 64-65 MPH.

[worthywads]

Download a speed app on your phone and then check your speed on the phone vs your speedo.  When my speedo says 70 MPH the app says I'm actually going 64-65 MPH.

The odometer accuracy is the important thing, does the app also let you measure distance traveled?

[JH27N0B]

At it's best, the one that got away from me - 69 roadrunner 440-6, 4-speed, 4.10 Dana - got 8 mpg...

Gawd I wish I had that one back!

My '71 V code super track pack 4:10 4 speed Challenger seems to do really well on the highway on the few trips I've gritted my teeth while getting in everyone's way driving 60 mph or so with the engine singing away in the neighborhood of 4000 rpm to go to some shows.  I never took detailed records but based on the gas I added and miles I put on, it seemed to be getting around 14 mpg or a bit better.  Most everyone tells me no way, but I've made the same trips to events in my 383 with 3.23 auto convertible and it used much more fuel, I was estimating 10 mpg or maybe a hair more, at best, with it.
Maybe it's a 383 thing. 

[dodj]

Could be the lack of glass in your car. Lots more drag that way....

[73440]

Posted by: worthywads
« on: Today at 03:32:54 PM »

    Insert Quote


Quote from: usraptor on Today at 02:54:01 PM

    Download a speed app on your phone and then check your speed on the phone vs your speedo.  When my speedo says 70 MPH the app says I'm actually going 64-65 MPH.


The odometer accuracy is the important thing, does the app also let you measure distance traveled?


I have used the Ulysse app for speedo, has mileage etc.

[jordan]

My stroker 520" six bbl get 6mpg.  My plugs look fine.  Runs real nice.  6mpg during break in.  6mpg at 4000miles.  And I have a tall rear and overdrive!  Try a little harder and you can get even less!!!!