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#1 |
Registered User
Join Date: Dec 2008
Location: orlando fl
Posts: 203
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str8 6 help
does anybody know how to get good gas mileage from this motor cause i dont even think im getting 10 in the city
any kind of help would help
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1978 c10 stepside Last edited by lil blue; 02-15-2010 at 10:18 PM. |
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#2 |
Registered User
Join Date: Jan 2009
Location: phoenix,AZ
Posts: 451
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Re: str8 6 help
250 or 296 st8 6 auto or manual, what is your reaer end ratio, 1bbl or 2bbl carb
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#3 |
Registered User
Join Date: Dec 2008
Location: orlando fl
Posts: 203
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Re: str8 6 help
its a 250 1bbl auto and i dont know my rear end ratio but it was getting around 10 mpgs now i dont even want to know
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1978 c10 stepside |
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#4 |
Registered User
Join Date: Jan 2009
Location: phoenix,AZ
Posts: 451
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Re: str8 6 help
I THINK that you have a 3.08 rear, and should be geting better that 10, i get 10MPG with my 351 CI V8 in my full size f$rd!!!!!
Last edited by tecky11; 02-15-2010 at 11:51 PM. Reason: wrong engine size |
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#5 |
Truck and auto performance nut
Join Date: Feb 2007
Location: McKinney,Texas
Posts: 3,848
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Re: str8 6 help
keep it tuned up and your tires properly inflated.
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Kurt - '68 GMC short step - NIB '09 LY6 6.0L crate motor w/mods, NIB '12 crate 4L85e w/billet 3k stall Circle D, 3.73 posi 12 bolt, DynaTech f-swap headers, 3/4 drop, handling mods, etc. - my toy '72 Chevy LWB C-10 Highlander - 350/350 ps/pb/tilt/ac - not original but close '06 Chevy TrailBlazerSS - LS2/4L70e - little black hot rod SUV - my DD '18 Kia Sorento - wife's econo-driver '95 Chevy S10 - reg cab shortbed, LS, 4.3, auto... my '68's powertrain and chassis build -links broken A surprise phase - carb to efi -links broken |
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#6 |
Registered User
Join Date: Dec 2008
Location: orlando fl
Posts: 203
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Re: str8 6 help
i always keep the tires full i should get a 350 get the same mpg but more power
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1978 c10 stepside |
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#7 |
Senior Member
Join Date: Jan 2007
Location: central pa
Posts: 428
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Re: str8 6 help
I installed a HEI and went with a larger air cleaner. I also put a higher geared rear in it. My buddy had a 4 on the tree and was able to go with a higher gear ratio and also ran taller tires.
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#8 |
Registered User
Join Date: Dec 2006
Location: Porter Ranch, CA
Posts: 978
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Re: str8 6 help
What a lot of people forget to verify is that their speedo is reading correctly. Maybe you are only getting 10 MPG, but with the number of screwed up speedo's I've seen, get it calibrated, then figure out what you have. I was off by 30% in mine!!!
If it is accurate and you're still barely getting 10 MPG, start troubleshooting, tuning up and doing all the little crap that most people will suggest... Here are some questions to answer for yourself. Are the float(s) leaking in the carb causing it to run fat? Or some other carb issue? Has the mileage changed recently or has it always sucked? Do your driving habits cause the mileage to change very much? |
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#9 |
Registered User
Join Date: Dec 2008
Location: orlando fl
Posts: 203
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Re: str8 6 help
no i just checked it like 10 mins ago its right and i drive it so slow people fly past me leaving the red lights i know its not the way i drive
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1978 c10 stepside |
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#10 |
Registered User
Join Date: Dec 2008
Location: orlando fl
Posts: 203
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Re: str8 6 help
i had the motor tuned one time and i did really good for about 2 weeks then it went to crap and i didnt touch anything
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1978 c10 stepside |
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#11 |
Registered User
Join Date: Jun 2009
Location: Newnan, GA
Posts: 485
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Re: str8 6 help
is there smoke coming out the tailpipe if so what color? Is there a fuel leak? Check the gap on your sprak plugs. There are a lot of little things you can do. i know a rebuild kit for the carb is less than 20 bucks.
I was getting about 16 mpg in my 6-er. Then the carb went south on me.
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#12 |
Six in a row makes it go...
![]() Join Date: Mar 2009
Location: Vacationland: Maine
Posts: 1,346
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Re: str8 6 help
The Rochester Carburetors book has a small section on Monojet Economy Modifications. It says to increase the main jet size one or two sizes, plug the APT, and cut not more than two full coils from the power spring.
That said, you should be getting better mileage already without these mods. An HEI helps a little too.
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67 C20 long step resto: http://67-72chevytrucks.com/vboard/s...d.php?t=342086 66 C10 long step build: http://67-72chevytrucks.com/vboard/s...=1#post3814790 CT to Alaska in a 67 C10: http://67-72chevytrucks.com/vboard/s...d.php?t=399224 “The height of sophistication is simplicity." - Clare Boothe Luce |
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