what's you best MPG?? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Beefcake · 02-11-2004, 12:28 PM

Give me some #s....

Looking to increase my MPG in my 1/2 ton would like to stay with a carb... but if you want to brag with your fi, feel free!!

What engine/trans and setup?

thanks!!

_Q_ · 02-11-2004, 12:51 PM

I'm running a 402 BBC, holley intake, and a 625cfm road demon. I've also got a 700r4. I get about 16-18 freeway, 10-12 in town.. depending on how far my foot goes.

JimKshortstep4x4 · 02-11-2004, 01:20 PM

71 longbed, 307/TH350/307 gears, 2wd, 16 mpg highway, 14 city.

Engine has a 4 bbl. Q jet.

Does not seem to vary if loaded or not.

Jim

**JIMs70GMC** · 02-11-2004, 01:31 PM

33" tires 4.10 gears 4speed, about 7 mph. When I fix the vacuum advance then back to about 11 mph. Q-jet. stock 350.

lukecp · 02-11-2004, 01:53 PM

13.2 is my best, usually around 12-13, mostly highway driving. 300hp 350/TH350/3.07 gears in a 3980lb truck

SWEET7T · 02-11-2004, 02:02 PM

327/350/3.07. 2wd and a 2bbl and points! 11-13 town, 11-13 highway (running 70-80mph). If I would slow it down (never) to 50's then it comes up to the upper teens but I've got better things to do than turn 2300rpms... (3g's at ~82mph)

mrein3 · 02-11-2004, 02:41 PM

3.73 rear. 4wd. Just over 13 is my best ever.
Usually around 9.5 while towing my boat.
3-5 in the winter which consists of warm it up 20 minutes, drive 1/4 mile across the lake, shut it off.

Grim Reaper · 02-11-2004, 03:20 PM

I think a few of those are a little off. Odometer is off from tires size I bet.

Best I have manage with a 88 FI 454, TH400, 3.73 and 235/85/16 E-rated hwy tires was 11.5 in a Suburban. Steady 70mph with 2800 ish on the tach.

That's as recorded by GPS for the miles and confirming my odometer is only off by 3/4 of mile over 300 miles on the current tires. It was a start engine drive 300 miles on the hwy deal. Normal driving to and from work including 38 miles of hwy a day against traffic it gets 9.5 with winter grade and long warm ups (She cold natured). I'm a set the cruise type also and run under 70.

With OD I can buy 14-15. Tall gears I can buy 12-14.

Best I did on my 75 Jimmy was 12.5 empty on 32's with a 3.08 gear. I towed a car back that same trip and was down to 8-9 area. The Odometer seemd fairly acurate but I never checked against a GPS when it had that combo. It seems to get about 9.75 on 35's with a 4.10 gear now with summer fuel and no top.

darcane · 02-11-2004, 04:39 PM

Just over 15mpg with a 400sb at ~75mph.

That's with 3.73 gears, a 5-spd (from a 1990 1/2 ton), and a lame EFI system (Holley Pro-jection 4). I don't have any good numbers with the 700R4 yet.

68 Suburban · 02-11-2004, 04:39 PM

17+ Adjusted for the tire size

Bowtie67 · 02-11-2004, 04:45 PM

15mpg around town 21mpg on highway, 350/ roller setup and Holley MPFI, 700R4 with 2200 Stall & 3.73 gears. Custom Crower Roller Cam 208/218 452/477 112LC, Performer RPM Heads, 10.2cr
But I should also add this is gonna change
new setup this summer includes, Loosing over 300lbs in truck,
New IFS, Four Link Rear, 414SBC 10.4cr, Fuller Roller Setup, 4.11 gears and New Holley StealthRam Setup.. Hoping to smoke a few Mustang Cobras..

72c10step · 02-11-2004, 05:57 PM

Quote:

Originally posted by Bowtie67
15mpg around town 21mpg on highway, 350/ roller setup and Holley MPFI, 700R4 with 2200 Stall & 3.73 gears. Custom Crower Roller Cam 208/218 452/477 112LC, Performer RPM Heads, 10.2cr
But I should also add this is gonna change
new setup this summer includes, Loosing over 300lbs in truck,
New IFS, Four Link Rear, 414SBC 10.4cr, Fuller Roller Setup, 4.11 gears and New Holley StealthRam Setup.. Hoping to smoke a few Mustang Cobras..

That's pretty sweet! Have you ever taken it to the dragway? It'd be cool to check that out someday!

Bowtie67 · 02-11-2004, 06:35 PM

The crower cam really smoothed things up and there was quite a bit of torque but the cam was more docile, I went from a Compcams 286HR to this, HUGE Difference, the 286HR WOuld smokem through 3 gears and really sounded awsum, but would load up in heavy city driving and out on the highway it really didn't really feel like it was there, more of a lets get it on type of cam, The new motor I'm hoping is gonna get a little more of both worlds, CompCams XE276 Marine Cam. Im putting in a 2 peice timing cover if it's not...

ts71281 · 02-11-2004, 06:43 PM

In my 70 SWB 1/2T 2WD and a 468 with a 3spd saginaw and 3.73 gears I can yank about 15 MPG on the interstate at 65MPH and 12 MPG in town if I keep my foot out of it.

Joe Hirdler

cdowns · 02-11-2004, 07:18 PM

4:10 gears 2004R tranny longbed with 350 about 300hp on the highway 75-80mph i get just under 17

cochran63 · 02-11-2004, 10:01 PM

Over the summer i had a 14:1 chevy 302 on alcohol that got 1/3 of a mpg, but when i have my 327 in i get around 14-15 mpg

bad 71 chevy · 02-11-2004, 10:06 PM

12.0 is my best

67dragtruck · 02-11-2004, 10:10 PM

Quote:

Originally posted by Bowtie67
The crower cam really smoothed things up and there was quite a bit of torque but the cam was more docile, I went from a Compcams 286HR to this, HUGE Difference, the 286HR WOuld smokem through 3 gears and really sounded awsum, but would load up in heavy city driving and out on the highway it really didn't really feel like it was there, more of a lets get it on type of cam, The new motor I'm hoping is gonna get a little more of both worlds, CompCams XE276 Marine Cam. Im putting in a 2 peice timing cover if it's not...

I feel your pain on the cam deal. I have the 300HR one in mine and with some huge rockers at that and I definitely know what you mean. Very tough to adjust with the EFI, hits a nasty lick, actually runs well, but tough to tune. Thinking of putting a smaller stick in mine too.

Tom

jku72 · 02-11-2004, 10:15 PM

My 68 burb gets 16 around town, 19 on the highway. I run a 350, 4 speed, and 3.07 rear.

Bowtie67 · 02-12-2004, 10:57 AM

Dragtruck, I ran that 286HR with a set of duel quads and had same issue with city driving as far as FI goes the eaiest I am able to figure is that you need at least a 112LC for best compatibility, What motor and setup are you running in that truck, just curious..

rn2fine · 02-12-2004, 12:07 PM

72 Burb, 2WD, 350, Vortec Heads, Headers, TH700R, 3.07 Rear, Edelbrock Performer Intake, Edelbrock 600 cfm, Average 15 mpg

68 Suburban · 02-12-2004, 02:55 PM

Quote:

Originally posted by rn2fine
72 Burb, 2WD, 350, Vortec Heads, Headers, TH700R, 3.07 Rear, Edelbrock Performer Intake, Edelbrock 600 cfm, Average 15 mpg

That combinations seems like it should be getting a lot better. What cam do you have?

rodnok1 · 02-12-2004, 02:59 PM

18 in the tow vehicle when the stock distrib broke, otherwise 12-13 max usually 8 around town, less if I whoop on it.

71402BB · 02-12-2004, 06:49 PM

In my 71 swb step
it has a mild 402 BB 10.5:1 268 comp cams cam balanced, 4-speed 3.73's and 26" tall tires I got 5mpg this summer with it! I hope to put 2.73's in this spring and hopefully I will double my mpg!

68 Suburban · 02-12-2004, 07:00 PM

Quote:

Originally posted by 71402BB
In my 71 swb step
it has a mild 402 BB 10.5:1 268 comp cams cam balanced, 4-speed 3.73's and 26" tall tires I got 5mpg this summer with it! I hope to put 2.73's in this spring and hopefully I will double my mpg!

5mpg!!!! Ouch!!! Be carefull with your gearing. You want to make sure you are cruising in a good range for the cam in your engine

02-11-2004, 12:28 PM	#1
Beefcake Registered User Join Date: Mar 2003 Location: Motor City Posts: 540	what's you best MPG?? Give me some #s.... Looking to increase my MPG in my 1/2 ton would like to stay with a carb... but if you want to brag with your fi, feel free!! What engine/trans and setup? thanks!! __________________ 72 GMC Camper Special 2500. currently has 350/350/14 bolt. 383 and 400 tranny is in the works.

02-11-2004, 01:31 PM	#4
JIMs70GMC user # 2756 Join Date: Jun 2001 Location: Chesapeake, Virginia Posts: 4,612	33" tires 4.10 gears 4speed, about 7 mph. When I fix the vacuum advance then back to about 11 mph. Q-jet. stock 350. __________________ 1970 K25, 8' stepside bed 350/465/205 44 up front, 60 in the rear 4.10s rolling on 33" Dunlop MTs 1986 K5, 350/465/208 Dana 60/14 bolt from a cucv 36" Super Swampers TSL/SX 1983 K20 w/ CUCV axles, 350/700R4/208 sitting on 37" Goodyears 1986 M1031 6.2 diesel, TH400/NP205 locker in the rear and a LS in the front, all stock for now..... 1986 K30, 350/400/205 dana 60 and 14 bolt. I kept the drivetrain. Body/bad and chassis are gone. 1981 K30, 350/465/205 dana 60 and dually 14 bolt. Has a G80, and a flat bed. Going to replace the flat bed. 1985 K20, 350/400/208 10 bolt and SF 14 bolt. I wonder where I can find some 1 tons. Hmmmmm

02-11-2004, 01:53 PM	#5
lukecp Formerly yellow72custom Join Date: May 2001 Location: Austin, TX Posts: 7,531	13.2 is my best, usually around 12-13, mostly highway driving. 300hp 350/TH350/3.07 gears in a 3980lb truck __________________ '72 Chevy C10 Mild 350/TH350/3.07. Ochre/White. Old high school ride. '70 GMC C2500 '62 327 4bbl/SM465/4.56-geared Dana 60. White/White. Project or parts truck. '97 Saturn SL DD. 1.9/5-speed. 40+ highway mpg

02-11-2004, 02:02 PM	#6
SWEET7T Try spinnin 4 rear tars Join Date: Sep 2003 Location: Salt Lake City, Utah Posts: 757	327/350/3.07. 2wd and a 2bbl and points! 11-13 town, 11-13 highway (running 70-80mph). If I would slow it down (never) to 50's then it comes up to the upper teens but I've got better things to do than turn 2300rpms... (3g's at ~82mph) __________________ SWEET7T 1970 C10, 2wd, LB, 307/TH350/3.08. PS, PB

02-11-2004, 02:41 PM	#7
mrein3 Registered User Join Date: Feb 2000 Location: Center City, MN, USA Posts: 3,254	3.73 rear. 4wd. Just over 13 is my best ever. Usually around 9.5 while towing my boat. 3-5 in the winter which consists of warm it up 20 minutes, drive 1/4 mile across the lake, shut it off. __________________ '70 cab, '71 chassis, 383, TH350, NP205. '71 Malibu convertible '72 Malibu hard top Center City, MN

02-11-2004, 12:51 PM	#2
_Q_ Registered User Join Date: Feb 2004 Location: San Diego Posts: 25	I'm running a 402 BBC, holley intake, and a 625cfm road demon. I've also got a 700r4. I get about 16-18 freeway, 10-12 in town.. depending on how far my foot goes.

02-11-2004, 01:20 PM	#3
JimKshortstep4x4 Senior Member Join Date: Jul 2001 Location: Muskegon,MI,USA Posts: 6,026	71 longbed, 307/TH350/307 gears, 2wd, 16 mpg highway, 14 city. Engine has a 4 bbl. Q jet. Does not seem to vary if loaded or not. Jim

02-11-2004, 03:20 PM	#8
Grim Reaper Registered User Join Date: Jul 2001 Location: Atlanta GA Posts: 1,704	I think a few of those are a little off. Odometer is off from tires size I bet. Best I have manage with a 88 FI 454, TH400, 3.73 and 235/85/16 E-rated hwy tires was 11.5 in a Suburban. Steady 70mph with 2800 ish on the tach. That's as recorded by GPS for the miles and confirming my odometer is only off by 3/4 of mile over 300 miles on the current tires. It was a start engine drive 300 miles on the hwy deal. Normal driving to and from work including 38 miles of hwy a day against traffic it gets 9.5 with winter grade and long warm ups (She cold natured). I'm a set the cruise type also and run under 70. With OD I can buy 14-15. Tall gears I can buy 12-14. Best I did on my 75 Jimmy was 12.5 empty on 32's with a 3.08 gear. I towed a car back that same trip and was down to 8-9 area. The Odometer seemd fairly acurate but I never checked against a GPS when it had that combo. It seems to get about 9.75 on 35's with a 4.10 gear now with summer fuel and no top. __________________ Grim-Reaper 70 Pontiac LeMans Sport Convertible, worlds longest resto in progress Looking for 71-72 2wd Blazer or Jimmy Project Last edited by Grim Reaper; 02-11-2004 at 03:22 PM.

02-11-2004, 04:39 PM	#9
darcane Registered User Join Date: Jun 2000 Location: Puyallup, WA Posts: 414	Just over 15mpg with a 400sb at ~75mph. That's with 3.73 gears, a 5-spd (from a 1990 1/2 ton), and a lame EFI system (Holley Pro-jection 4). I don't have any good numbers with the 700R4 yet. __________________ *Mike Lackey* '68 C10

02-11-2004, 04:39 PM	#10
68 Suburban Registered User Join Date: Oct 2000 Location: From Chicago, Live in Phoenix, AZ Posts: 6,802	17+ Adjusted for the tire size __________________ Just sitting here contemplating contemplation.

02-11-2004, 04:45 PM	#11
Bowtie67 Registered User Join Date: Jan 2004 Location: NH Posts: 2,266	15mpg around town 21mpg on highway, 350/ roller setup and Holley MPFI, 700R4 with 2200 Stall & 3.73 gears. Custom Crower Roller Cam 208/218 452/477 112LC, Performer RPM Heads, 10.2cr But I should also add this is gonna change new setup this summer includes, Loosing over 300lbs in truck, New IFS, Four Link Rear, 414SBC 10.4cr, Fuller Roller Setup, 4.11 gears and New Holley StealthRam Setup.. Hoping to smoke a few Mustang Cobras.. Last edited by Bowtie67; 02-11-2004 at 04:48 PM.

02-11-2004, 06:35 PM	#13
Bowtie67 Registered User Join Date: Jan 2004 Location: NH Posts: 2,266	The crower cam really smoothed things up and there was quite a bit of torque but the cam was more docile, I went from a Compcams 286HR to this, HUGE Difference, the 286HR WOuld smokem through 3 gears and really sounded awsum, but would load up in heavy city driving and out on the highway it really didn't really feel like it was there, more of a lets get it on type of cam, The new motor I'm hoping is gonna get a little more of both worlds, CompCams XE276 Marine Cam. Im putting in a 2 peice timing cover if it's not...

02-11-2004, 06:43 PM	#14
ts71281 Registered User Join Date: Apr 2003 Location: Maple Grove, MN Posts: 497	In my 70 SWB 1/2T 2WD and a 468 with a 3spd saginaw and 3.73 gears I can yank about 15 MPG on the interstate at 65MPH and 12 MPG in town if I keep my foot out of it. Joe Hirdler

02-11-2004, 07:18 PM	#15
cdowns Senior Member Join Date: Jan 2003 Location: daytonabeach Posts: 22,956	4:10 gears 2004R tranny longbed with 350 about 300hp on the highway 75-80mph i get just under 17 __________________ 71c-10 350/2004r/4:11 lowered3/4 longbed/dead by hurricane MEANING OF DEATH::::: SOMEBODY ELSE GETS YOUR STUFF DONT BELIEVE EVERYTHING YOU THINK TAKE MY ADVISE;I DON'T USE IT ANYWAY

02-11-2004, 10:01 PM	#16
cochran63 Registered User Join Date: Jan 2004 Location: Oklahoma Posts: 1,057	Over the summer i had a 14:1 chevy 302 on alcohol that got 1/3 of a mpg, but when i have my 327 in i get around 14-15 mpg __________________ Youth soon passes away, but immaturity can last a life time.



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02-11-2004, 10:06 PM	#17
bad 71 chevy Registered User Join Date: Jun 2000 Location: Omaha NE 68122 Posts: 637	12.0 is my best __________________ 71 Chevy C/10 lwb 350 5 speed nv3500 3.73 rear end 2.5" Front Drop and 4" in the back Edelbrock perfomer rpm manifold Edelbrock 600 cfm carb Headmen headers

02-11-2004, 10:15 PM	#19
jku72 Registered User Join Date: Jan 2002 Location: cornville, maine Posts: 659	My 68 burb gets 16 around town, 19 on the highway. I run a 350, 4 speed, and 3.07 rear. __________________ jku Cornville, Maine 68 C10 burb 42 Willys MB 46 Dodge WF-32 1.5 ton 53 & 56 Olds' 60 Cadillac 22 Dodge Brothers

02-12-2004, 10:57 AM	#20
Bowtie67 Registered User Join Date: Jan 2004 Location: NH Posts: 2,266	Dragtruck, I ran that 286HR with a set of duel quads and had same issue with city driving as far as FI goes the eaiest I am able to figure is that you need at least a 112LC for best compatibility, What motor and setup are you running in that truck, just curious..

02-12-2004, 12:07 PM	#21
rn2fine Registered User Join Date: Jan 2004 Location: Arizona Posts: 157	72 Burb, 2WD, 350, Vortec Heads, Headers, TH700R, 3.07 Rear, Edelbrock Performer Intake, Edelbrock 600 cfm, Average 15 mpg __________________ 72 C10 Burb 350 700R4 70 C20 LWB 350 Crate TH400 68 Chevelle

02-12-2004, 02:59 PM	#23
rodnok1 Registered User Join Date: Jun 2003 Location: Linden, North Carolina Posts: 617	18 in the tow vehicle when the stock distrib broke, otherwise 12-13 max usually 8 around town, less if I whoop on it. __________________ 64 Panel Rebuild Pics Clutch Replacement and Borg Warner T10 Trans Rebuild 64 Panel 1/2 Ton 350cubes/400hp BorgWarner t-10 3:73 Auburn Posi

02-12-2004, 06:49 PM	#24
71402BB now thats a true COON DOG Join Date: Nov 2000 Location: Franconia, NH Posts: 1,977	In my 71 swb step it has a mild 402 BB 10.5:1 268 comp cams cam balanced, 4-speed 3.73's and 26" tall tires I got 5mpg this summer with it! I hope to put 2.73's in this spring and hopefully I will double my mpg! __________________ current project 67 402BB stout th350 3.08's with a locker. Plan on tubs 18.5's out back! (thanks Burnsman!) 71 SWB Stepside, was a 250, now is a 402 Big Block with 4 speed and 3.73's ( was crushed by a tree, bed sold, motor pulled) was my first truck!... oh well... 72 LWB 4x4 350 4-speed 3.08's posi wearing army olive drab green (SOLD!) 68 BURB 50TH LOOKALIKE work in progress, soon to have 250-I6 with a 3-speed on the tree 4.11's and posi ( currently sitting in back yard tarped awaiting time, $$$, and lots of love!) 67 1 TON- work truck 396 sm 420 4-speed, flat bed 4.57 gears "big red" (my first landscape truck, very rusty and crusty! but still gets the job done when needed!)

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