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#1 |
Registered User
Join Date: Oct 2008
Location: JAY, NY
Posts: 176
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7 MPG!!!! Yikes!!!
in the past couple of days drivin the green machine..... i figured out the mileage and its around 7..... so anyway i wanna get rid of my 5.14's and get a rearend a little higher geared.... what is the best way to go about this? i have a buddy that gave me a rearend (4.10's) and cast iron 4 speed out of a 84 c20.... the truck had a 6.2 that we put in another truck i am unsure about it fitting in the 67... i im pretty sure the bell housings will interchange but dunno....
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04 Chevy Colorado Z71 4X4 76 Chevy C-10 Custom Deluxe (sold) 67 Chevy C-30 1 Ton 9' stepper 6.5 Turbo Diesel |
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#2 |
Junior Member
Join Date: Dec 2006
Location: Southeast Missouri
Posts: 2,436
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Re: 7 MPG!!!! Yikes!!!
It all depends on your engine, transmission, rear gears and tire size what mpg you will get.
I had a 350 in my '71 with the old type 4 speed, 3.73 rear gears and 31's on the back, with that setup I was getting 12-14 mpg depending on how I drove. I am not sure what I will get now with the 454 and the same setup. I use to have a '72 GMC with a 350, old style 4 speed and 4.1? in the rear with stock tires and normally got about 10 mpg. I am sure others will chime in with more information. Danny
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'67 Chevy C-20 short stepper - build complete, 454/SM-465. '75 C-30 Single Cab DRW-350 small block/NP-435. '77 GMC-6500 Dump Truck, 427 Tall Deck. '92 GMC K-3500 Duallie, 454/4L80E. |
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#3 |
Registered User
Join Date: Oct 2008
Location: JAY, NY
Posts: 176
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Re: 7 MPG!!!! Yikes!!!
duh i should have metnioned that! lol im running the factory 327/ sm420 (7:1 1st gear granny take off in third ) 4 speed.... with the 5.14's in the back and im runnin 265-75x16 at 45mph im crankin about 2600 rpm
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04 Chevy Colorado Z71 4X4 76 Chevy C-10 Custom Deluxe (sold) 67 Chevy C-30 1 Ton 9' stepper 6.5 Turbo Diesel |
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#4 | |
I have a radical idea!
Join Date: Jan 2005
Location: Sweet Home Alabama!
Posts: 6,513
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Re: 7 MPG!!!! Yikes!!!
Quote:
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'67 C-30 Dually Pickup 6.2 Turbo Diesel, NP435 ‘72 C-10 SWB , 350 4bbl, TH350 '69 C-10 SWB , 250 L6, 3 OTT '69 GMC C3500, dump truck, 351 V6, NP435 '84 M1009 CUCV Military Blazer 67 C-30 Turbodiesel build thread http://67-72chevytrucks.com/vboard/s...d.php?t=254096 My trucks http://s226.photobucket.com/albums/d...ediafilter=all Member of the 1-Ton Club! |
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#5 |
Registered User
Join Date: May 2009
Location: Eliot, Maine
Posts: 1,314
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Re: 7 MPG!!!! Yikes!!!
i have gotten 10-11mpg with mixed driving in my 72 burb 3/4 ton 2wd 307 3onthetree 4.57 gear. i have a 4.10 third member ready to go in the axle and that should get me in the 12-14mpg range, especially in highway driving. i don't go over 55 for long distances 'cause the engine screams with such speed gearing. also planning to add the factory borg warner OD unit to the trans and that should get me in the 16-18mpg range if i keep to 60mph.
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#6 |
Registered User
Join Date: Nov 2009
Location: stoddard nh
Posts: 693
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Re: 7 MPG!!!! Yikes!!!
sorry for hacking post, what is the borg OD unit, and does it fit only on certain trannys or pretty universal? thanks and sorry again
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#7 |
Registered User
Join Date: Mar 2009
Location: independence mo
Posts: 2,111
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Re: 7 MPG!!!! Yikes!!!
I only get about 7 1/2 or 8.
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I'm not as good as I once was, But I'm as good once as I ever was. |
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#8 |
Registered User
Join Date: Oct 2008
Location: JAY, NY
Posts: 176
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Re: 7 MPG!!!! Yikes!!!
i want to go that route so bad but i am gonna wait till the 327 goes which if this trans and rear works ill be all set..... does anyone know if it will fit?
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04 Chevy Colorado Z71 4X4 76 Chevy C-10 Custom Deluxe (sold) 67 Chevy C-30 1 Ton 9' stepper 6.5 Turbo Diesel |
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#9 |
Registered User
Join Date: May 2009
Location: Eliot, Maine
Posts: 1,314
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Re: 7 MPG!!!! Yikes!!!
if i had tons of money a 6.5 with banks kit and a mechanical clutch 6 speed (with .7 5th and .52 6th gear) and a 4.10 rear end would be awesome in my 72 burb 3/4 ton. soo much torque and the fact that they are not high revving and you can go insane with the overdrive ratios!
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#10 | |
I have a radical idea!
Join Date: Jan 2005
Location: Sweet Home Alabama!
Posts: 6,513
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Re: 7 MPG!!!! Yikes!!!
Quote:
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'67 C-30 Dually Pickup 6.2 Turbo Diesel, NP435 ‘72 C-10 SWB , 350 4bbl, TH350 '69 C-10 SWB , 250 L6, 3 OTT '69 GMC C3500, dump truck, 351 V6, NP435 '84 M1009 CUCV Military Blazer 67 C-30 Turbodiesel build thread http://67-72chevytrucks.com/vboard/s...d.php?t=254096 My trucks http://s226.photobucket.com/albums/d...ediafilter=all Member of the 1-Ton Club! |
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#11 | |
I have a radical idea!
Join Date: Jan 2005
Location: Sweet Home Alabama!
Posts: 6,513
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Re: 7 MPG!!!! Yikes!!!
Quote:
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'67 C-30 Dually Pickup 6.2 Turbo Diesel, NP435 ‘72 C-10 SWB , 350 4bbl, TH350 '69 C-10 SWB , 250 L6, 3 OTT '69 GMC C3500, dump truck, 351 V6, NP435 '84 M1009 CUCV Military Blazer 67 C-30 Turbodiesel build thread http://67-72chevytrucks.com/vboard/s...d.php?t=254096 My trucks http://s226.photobucket.com/albums/d...ediafilter=all Member of the 1-Ton Club! |
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#12 |
Senior Member
Join Date: Apr 2002
Location: Help! I'm in an office park with its own network of freeways!
Posts: 470
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Re: 7 MPG!!!! Yikes!!!
With the 400, I would get 12-14 in my truck. With the 427, I get 7-8. Same trans & rear end (SM420 & 4.10) though.
I can hear my wallet being sucked through that Qjet. ![]()
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'67 C20--427 tall deck/SM420, 4.10 HO52 (Michigan has not been kind to the Old Man) '95 Caprice--355 LT1/T56/3.42 8.5" 10-bolt (daily driver, almost 300k on the chassis) '07 Outback--wife's car. 125k & counting. No head gasket or transmission issues yet. *fingers crossed* Last edited by CE20934; 03-26-2010 at 10:00 PM. |
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#13 |
Registered User
Join Date: Jun 2009
Location: Arlington Texas
Posts: 602
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Re: 7 MPG!!!! Yikes!!!
I have a 70 with a 350 bored 60 over with a 350 tranny. I calculated my last trip pulling a pop up trailer and my Harley and camping and fishing gear for a week on the beach in the bed at just over 14 MPH. Im guessing its driving style with it loaded cause I dont get that good when its not loaded down.
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1970 GMC truck ![]() 1988 Harley 1200 Sportster ![]() |
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#14 |
Cops, ha, catch me if you can!
Join Date: Jun 2009
Location: Santa Barbara, CA.
Posts: 271
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Re: 7 MPG!!!! Yikes!!!
FYI to all. A common misconception, is that the weight of what your hauling or towing will affect your mileage. The truth is, If your on the freeway, on a long distance drive, it will not affect your MPG. Now as far as stop and go traffic or city driving, that is where you'll see the difference.
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72 C-10 Stepper 350/TH350 3.73 in the back Edelbrock intake and Carb Hooker Comp Headers 275/60R15 on Rallies ![]() ![]() Last edited by gonzo6869; 03-26-2010 at 11:41 PM. |
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#15 |
Devil's in the Details
Join Date: Sep 2008
Location: Southern Utah
Posts: 353
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Re: 7 MPG!!!! Yikes!!!
I used to get a consistent 7.5 mpg around town and 10 mpg highway in my K10 Suburban when it had a q-jet 355 / 700R4 / 3.07 gear ratio and 31" tire setup. I'm hoping for 11-12 with the TBI 454 / 4L80E / 4.11 ratio and 35" tires.
If I was interested in fuel mileage I'd drive something else.
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'70 K10 Suburban - TBI 454, 4L80E, NP241C, Dana 60 & 44 - The 10+ Year Project Thread Datsun 240Z, 510 2 door and an old Honda motorcycle |
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#16 | |
I have a radical idea!
Join Date: Jan 2005
Location: Sweet Home Alabama!
Posts: 6,513
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Re: 7 MPG!!!! Yikes!!!
Quote:
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'67 C-30 Dually Pickup 6.2 Turbo Diesel, NP435 ‘72 C-10 SWB , 350 4bbl, TH350 '69 C-10 SWB , 250 L6, 3 OTT '69 GMC C3500, dump truck, 351 V6, NP435 '84 M1009 CUCV Military Blazer 67 C-30 Turbodiesel build thread http://67-72chevytrucks.com/vboard/s...d.php?t=254096 My trucks http://s226.photobucket.com/albums/d...ediafilter=all Member of the 1-Ton Club! Last edited by 67_C-30; 03-27-2010 at 10:44 AM. |
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#17 |
Registered User
Join Date: May 2009
Location: Eliot, Maine
Posts: 1,314
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Re: 7 MPG!!!! Yikes!!!
sounds like someone slept through their physics 1 class! if you take the drag racer (crude) formula for determining power to weight, etc....100 pounds = 10 horse power. you start to see why you need to expend more weight you are moving, the more energy is used to move it. unless you are in a vaccum, it takes some energy to maintain that speed also. then you add in air and tire friction.....
my dad can get 18mpg out of his 87 burb 1/2 ton 2wd iwith 350, OD and 3.73 rear. he gets like 8-10mpg when he is hauling the family camper.....a '71 holiday trav'ler 23 footer that weighs 6,000 pounds loaded. |
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#18 |
Registered User
Join Date: Feb 2010
Location: Oakhurst, Kalifornia
Posts: 77
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Re: 7 MPG!!!! Yikes!!!
67_C30,,,,AWESOME!!! I get about 7 or 8 in my pig,, 400BB400trans, not sure of the rear ratio yet, I heard they came with 3.08 behind all BB,,,,I 'll have to pull the cover some day here and count.
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SEMPER FI 96 F350 CC/4X/7.3/ZF5 77 F150 SB/4X/NP435/NP205 70 C10 400/400 63 F250 4X/T98/NP205 |
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#19 | |
Account Suspended
Join Date: Dec 2008
Location: indisclosed
Posts: 1,515
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Re: 7 MPG!!!! Yikes!!!
Quote:
One question i had about the 6.2 was that the fuel pump appears to be a stock type identical to the gas sbc/bbc? i thought diesels need hi-pressure fuel pumps? |
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#20 |
Registered User
![]() Join Date: Sep 2008
Location: Willard,Ohio
Posts: 87
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Re: 7 MPG!!!! Yikes!!!
thats a lift pump. that pump supplies the injection pump. in that video of the 6.2 running, he is manualy operaterating the throttle on the injection pump.
Last edited by nicks05z71; 03-28-2010 at 10:47 PM. |
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#21 | |
I have a radical idea!
Join Date: Jan 2005
Location: Sweet Home Alabama!
Posts: 6,513
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Re: 7 MPG!!!! Yikes!!!
Quote:
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'67 C-30 Dually Pickup 6.2 Turbo Diesel, NP435 ‘72 C-10 SWB , 350 4bbl, TH350 '69 C-10 SWB , 250 L6, 3 OTT '69 GMC C3500, dump truck, 351 V6, NP435 '84 M1009 CUCV Military Blazer 67 C-30 Turbodiesel build thread http://67-72chevytrucks.com/vboard/s...d.php?t=254096 My trucks http://s226.photobucket.com/albums/d...ediafilter=all Member of the 1-Ton Club! |
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#22 | |
I have a radical idea!
Join Date: Jan 2005
Location: Sweet Home Alabama!
Posts: 6,513
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Re: 7 MPG!!!! Yikes!!!
Quote:
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'67 C-30 Dually Pickup 6.2 Turbo Diesel, NP435 ‘72 C-10 SWB , 350 4bbl, TH350 '69 C-10 SWB , 250 L6, 3 OTT '69 GMC C3500, dump truck, 351 V6, NP435 '84 M1009 CUCV Military Blazer 67 C-30 Turbodiesel build thread http://67-72chevytrucks.com/vboard/s...d.php?t=254096 My trucks http://s226.photobucket.com/albums/d...ediafilter=all Member of the 1-Ton Club! |
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#23 | |
Registered User
Join Date: Feb 2010
Location: Oakhurst, Kalifornia
Posts: 77
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Re: 7 MPG!!!! Yikes!!!
Quote:
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SEMPER FI 96 F350 CC/4X/7.3/ZF5 77 F150 SB/4X/NP435/NP205 70 C10 400/400 63 F250 4X/T98/NP205 |
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