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Old 02-25-2013, 03:00 PM   #1
86c20
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fuel report

ok guys went on a trip to NH to get a truck that i now dont want lol. but anyway i used my k30 6.2 loaded i got 9.8mpg with my foot to the floor the hole time. dam she needs more power lol.

what are you guys geting out of your trucks?
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1986 c20 "the hillbilly" 350 sm465 3.42gears 21mpg at 70mph
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1978 monte carlo 350 350th with 2.73 gears. no rust. sc car
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Old 02-25-2013, 06:28 PM   #2
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Re: fuel report

7.75 ....454.....empty.....i dont even wanna know what it is towing...
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Old 02-25-2013, 07:52 PM   #3
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Re: fuel report

Highway
1976 6.5 NA 5sp 4x4 17mpg 70mph
M1008 6.2 NA TH400 4x4 11mpg 55mph max
2000 6.5 TD 5sp 2wd 21mpg 70mph I've gotten 23 but it's an outlier typically she runs 20-21.

Town
1976 6.5 NA 5sp NP208 4x4 14mpg
M1008 6.2 NA TH400 NP208 4x4 9-10mpg
2000 6.5 TD 5sp 2wd 18mpg

LT265 70 R16 tires on all three
The CUCV has 4.56:1 axles... According to my spreadsheet... at 55mph she tachs out at 2100. That sounds about right. At 65 she should be turning 2600 and it sounds like the engine is trying to climb out from under the hood.

The other two have 3.73:1 axles. They tach out at roughly 2100 at 70mph.

I think the CUCV needs a 4L80.
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1967 Dodge W200 B383, NP420/NP201 SOLD
1969 Dodge Polara 500 B383, A833 SOLD
1972 Ford F250 FE390, NP435/NP205 SOLD
1976 Chevy K20, 6.5L, NV4500/NP208 SOLD
1986 M1008 CUCV SOLD
2000 GMC C2500, TD6.5L, NV4500
2005 Chevy Silverado LS 2500HD 6.0L 4L80E/NP263
2009 Impala SS LS4 V8


RTFM... GM Parts Books, GM Schematics, GM service manuals, and GM training materials...Please include at least the year and model in your threads. It'll be easier to answer your questions.
And please let us know if and how your repairs were successful.
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Old 02-25-2013, 08:32 PM   #4
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Re: fuel report

4l80e and a gear venders lol
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1986 c20 "the hillbilly" 350 sm465 3.42gears 21mpg at 70mph
1985 k30 "the ice cream truck from hell" no rust az truck
197-8??? c30 "ramp truck" 454
1978 monte carlo 350 350th with 2.73 gears. no rust. sc car
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Old 02-25-2013, 11:44 PM   #5
meatwagon83
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Re: fuel report

i get about 10 with mine, 454 th400 3.73 one ton crew
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Old 02-25-2013, 11:50 PM   #6
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Re: fuel report

Just got 12.8 this weekend. Mostly highway, kept it under 65.
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1996 GMC Sierra SLE 3500 DRW, 4x4, EC/LB, Vortec 454, NV-4500, BW-4401, AAM 925 & AAM 1050
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Old 02-26-2013, 12:17 AM   #7
INSIDIOUS '86
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Re: fuel report

I am about 5-10 city and 13hwy cruising at 3krpm at 60mph
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Old 02-26-2013, 12:43 AM   #8
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Re: fuel report

'85 crew, 454, t400, 4:56's, 38.5 swamps.$200-$220 to fill both tanks, 200 miles to empty both tanks. around 180 in town
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Old 02-26-2013, 01:22 AM   #9
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Re: fuel report

Quote:
Originally Posted by dieseldawg142 View Post
'85 crew, 454, t400, 4:56's, 38.5 swamps.$200-$220 to fill both tanks, 200 miles to empty both tanks. around 180 in town
daggone man! i thought mine was bad at about 140 a tank
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Old 02-26-2013, 01:30 AM   #10
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Re: fuel report

ya, right now we're paying $1.29 a liter (frickin metric) & there's just over 4 liters in a gallon. same truck 15 yrs ago was $80-$90
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Old 02-26-2013, 01:35 AM   #11
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Re: fuel report

I'm
At 50$ a tank in premium to fill at $3.97 a gal.
That's a good sack tap for you there
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build thread !http://67-72chevytrucks.com/vboard/s...d.php?t=577217
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Old 02-26-2013, 07:25 AM   #12
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Re: fuel report

Last summer I was getting 23mpg. 1987 R10 6.2 diesel NA 700R4 3.08. Mixed driving, 58 in country, 68 on highway, posted speed in city. Rear end is out right now and diesel is $4.25!
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Old 02-26-2013, 02:03 PM   #13
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Re: fuel report

diesel here is 472 a gal. and regualr gas is 472 or better a gal. in my 86 i get 200 miles a tank. witch comes out to be 14mpg with a top speed of 45mph. my 85 i get 200 out of it for 50 bucks almost. 50-60 bucks depending on what i do.
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1986 c20 "the hillbilly" 350 sm465 3.42gears 21mpg at 70mph
1985 k30 "the ice cream truck from hell" no rust az truck
197-8??? c30 "ramp truck" 454
1978 monte carlo 350 350th with 2.73 gears. no rust. sc car
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Old 02-26-2013, 04:08 PM   #14
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Re: fuel report

In my 74 shortbed 31 in tires 305/350 trans I get 10mpg that's street, don't get on the highway, so not sure on that number...
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Old 02-26-2013, 04:17 PM   #15
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Re: fuel report

89 TBI 350 K5, 700r4, 33x12.5x15, very tired 273k engine

full tank before last only netted me 9.62 mpg
filled up last night and came up with 11.66 mpg

No idea what was different. Prior to the 9.62 tank I'd overhauled the fuel system (new pump/sender/fuel filter/rebuilt TBI & new injectors)

I have a new EGR valve to swap in, hoping that will help me some.

I buy real gas, hovers over $3.60/gal here.
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Old 02-26-2013, 09:14 PM   #16
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Re: fuel report

6.24 in town, 11.2 HWY last time I checked. '83 K20, mild 355, TH400, NP208, 4.10 gears, 38x15.50 MT Baja Claw Radials.
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Old 02-26-2013, 09:51 PM   #17
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Re: fuel report

The 81 454/400/205/4:10 on 33s around 7-8. 82 6.2/A833/208/3.73 6" lift on 35s around 15-16 on highway this winter,86 350/465/208/4.10 7" lift on 35s around 10-11. Not sure about the old C20,wife drives it mostly,just keep filling it up!!!
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Old 02-26-2013, 10:46 PM   #18
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Re: fuel report

don't want to know but seems as thought the 502 is always thirsty. just happy to have 2 tanks until it's time to pay..saw premium at $4.19 a gallon yesterday! still a fun ride when i drive it. may check some day.
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Old 02-26-2013, 11:30 PM   #19
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Re: fuel report

Ive never checked and probably won't. I know it's crappy so I just know I just put 20 bucks in at a time and that lasts about two days lol.
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