What kind of gas mileage do you get with your 67-72? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Zone47 · 10-01-2018, 02:52 PM

... and what is your engine/tranny/rear end ratio?

I know most people don't care about fuel mileage but I noticed my 68 C10 was sucking gas like crazy so I started checking and am only getting 10.5 mpg.

I'm just puttering around town and to a few car shows now and then, nothing fast or aggressive.

So my setup is a 350 with pretty much stock cam and crappy 8.5:1 compression, an Edelbrock (quadrajet type) carb and headers. The tranny is a Turbo 400/stock torque converter and the rear end is a 12 bolt 3:08 limited slip.

I was thinking this truck sould normally get around 14 or 15 mpg. Maybe it's because the tires are larger and the body is not aerodynamic?

Ok so waddaya got and what's your mileage looking like?

**mike1971c10** · 10-01-2018, 03:04 PM

I have just about the same running gear, but with a 350 tranny. I think the most I've gotten is 12 mpg. Maybe someone else gets better mpg
mike

**Smitty** · 10-01-2018, 03:04 PM

I'm getting about the same as you. 60 over 350 edelbrock 4bbl. 700r4 3:56 posi.

Barnfind46 · 10-01-2018, 03:04 PM

12 to 14 MPG is not out of reach.Keep your tire pressure at the top of the safe usable range for your tires and keep it in good tune and you should do better. I do know that fuel with ethanol tends to drop mileage a bit. Mine is a C-20 with a 327, TH 350 and 3.73 gears. I get about 14 to 15 MPG.

P7M89MM · 10-01-2018, 03:11 PM

6-7mpgs

. ZZ502, built th350, 3200 stall, 3.73 posi.

dfwright · 10-01-2018, 03:49 PM

I have stock 350, stock quadrajet, stock TH350 transmission with .308 gears, and I get between high 12 to mid 13 mpg, depending on where and how I'm driving

**Steeveedee** · 10-01-2018, 04:37 PM

Like my sig says, 400/400THM/3.54 axle, factory equipment, except the engine and trans have been rebuilt. I haven't checked it without the travel trailer; when towing that, I get 7 MPG. I recall my FiL telling me it used to get 13 mpg, but we put a 12" taller camper shell on it, so it's going to have dropped because of that.

**RenoKeene** · 10-01-2018, 04:56 PM

I'm not much help because I really don't care, I just enjoy.
402 /400 /3.08 posi

tdangle · 10-01-2018, 05:08 PM

Around 14 mpg with a stock 350, 200r4 trans and 4.10 gears. This is mostly around town with a little freeway at 70 mixed in.

Chris_oz · 10-01-2018, 06:18 PM

stock 350, 4 speed, 4.57 diff on 8.75r16.5 tyres, if I sit on or under 60, its 15mpg.
any faster and it drops to 12mpg.
Bone stock in every way, 72k on clock, stock Qjet.

OregonNed · 10-01-2018, 06:58 PM

I get 12 ish with the non-ethanol premium I use.

72c20customcamper · 10-01-2018, 07:12 PM

Really 10 mpg around town is about the norm for a truck made when gas was 45 cents a gallon. Mine gets 12 on the highway doing 60. And that's in 4200lb box.

Andy4639 · 10-01-2018, 07:19 PM

71 with 2014 LS 6.0 and 4L80-e trans. 4:10 gears get 16-18 running 75-80 MPH with the AC on.

Ramp truck might get 12 with 350 and a granny 4 speed in it. No idea what rear end gears are.

Willys47 · 10-01-2018, 08:32 PM

460 / 400 trans / 373 rearend I cant pass a gas station .

custom10nut · 10-01-2018, 09:05 PM

I’m satisfied if I average 13-15 on the highway. I will stop for gas at 200ish miles, but try not to go less than an 1/8th before stopping. If I put a load, or have long hills, and the ol girl drinks like a sailor on shore leave. Doesn’t matter though, she ain’t goin nowhere

I run a standard 350/4bbl TH350, and 3.73 diff

weim55 · 10-01-2018, 09:10 PM

SWB fleet 1/2 ton, '99 roller cam 350 9.8 compression w/ mild cam, Edelbrock performer intake and AFB carb, headers, TH400 w/2500 stall, 3.54 rear. 15mpg @ crystal 65mph, 11mpg @ 75mph, 10-12mpg mixed driving. 10mpg pulling the race car on a trailer @ 60 mph. 5000-7500 feet elevation.

In my years of engine building I found a typical V8 will get one additional mile per gallon per point of raised compression.......

Steve weim55 Colorado

**special-K** · 10-01-2018, 09:13 PM

I don't want to talk about it!

It sucks now, but used to get a steady 12.5 no matter how I drove, hiway or country roads. It's been more like 10 in more recent years. I put different heads on a couple years ago and now it seems to be just under 10.... '72 K2500 350/TH350/4.10 with 285/75-16 Goodyear Duratracs

gvw5400 · 10-01-2018, 09:23 PM

LWB fleet 1/2 ton, 350 300 h.p. cam, Edelbrock performer RPM, 750 cfm AFB, ramhorns ,2.5 true dual exhaust, CH 465 4 spd, 3.73 axle ratio. 15.25 mpg @ 65-70 mph 5000' to 9000' elevation.

All the Best, Dirk

Zone47 · 10-01-2018, 09:28 PM

Hmmm! I guess I'll just some high compression heads, an air gap performer, a 280/460 cam and not worry about it. It sounds like it will probably at least still get 10 mpg with all that, but at least run better.

**Fbks_Cruiser** · 10-01-2018, 09:30 PM

72 K2500. 350/TH 350, 4:10, 235/85 R16 tires, HEI, Eldebrock 1406 carb, RV cam. 10-11 mph mixed highway and town driving using gps since my speedo is off by about 10%.

lutronjim · 10-01-2018, 09:44 PM

My 70 C10 with 307 4 barrel when new got 16mpg on highway when driven for mileage. I upgraded to LC9 with 65E and now driven for mileage on highway gets 21.

**Steeveedee** · 10-01-2018, 10:00 PM

Quote:

Originally Posted by RenoKeene

I'm not much help because I really don't care, I just enjoy.
402 /400 /3.08 posi

I don't know if I've said it before, but that is one SWEET truck!.

poway · 10-01-2018, 10:35 PM

1968 GMC half ton fenderside. Stock 250 six, turbo 400 trans, 3.54 rear end. My daily driver for about 2 years. 13-15 mpg.

**jocko** · 10-01-2018, 10:46 PM

Quote:

Originally Posted by Zone47

Hmmm! I guess I'll just some high compression heads, an air gap performer, a 280/460 cam and not worry about it. It sounds like it will probably at least still get 10 mpg with all that, but at least run better.

That's the spirit. Just remember - it takes MANY MANY years of spent gas money before you'd have paid what it would have required to have bought a brand new truck today that MIGHT do maybe 5-10 mph better in the fuel economy department. Drive and enjoy

weim55 · 10-01-2018, 11:17 PM

Like to hear from some six-cylinder people.......

10-01-2018, 02:52 PM	#1
Zone47 Registered User Join Date: Sep 2014 Location: Richfield, Oh Posts: 112	What kind of gas mileage do you get with your 67-72? ... and what is your engine/tranny/rear end ratio? I know most people don't care about fuel mileage but I noticed my 68 C10 was sucking gas like crazy so I started checking and am only getting 10.5 mpg. I'm just puttering around town and to a few car shows now and then, nothing fast or aggressive. So my setup is a 350 with pretty much stock cam and crappy 8.5:1 compression, an Edelbrock (quadrajet type) carb and headers. The tranny is a Turbo 400/stock torque converter and the rear end is a 12 bolt 3:08 limited slip. I was thinking this truck sould normally get around 14 or 15 mpg. Maybe it's because the tires are larger and the body is not aerodynamic? Ok so waddaya got and what's your mileage looking like?

10-01-2018, 03:04 PM	#2
mike1971c10 Senior Member Join Date: May 2012 Location: phoenix az Posts: 452	Re: What kind of gas mileage do you get with your 67-72? I have just about the same running gear, but with a 350 tranny. I think the most I've gotten is 12 mpg. Maybe someone else gets better mpg mike __________________ my build thread http://67-72chevytrucks.com/vboard/s...d.php?t=522167 vietnam vet 67-68

10-01-2018, 03:04 PM	#3
Smitty Senior Member Join Date: Dec 1999 Location: Spring Valley, Ca. Posts: 1,137	Re: What kind of gas mileage do you get with your 67-72? I'm getting about the same as you. 60 over 350 edelbrock 4bbl. 700r4 3:56 posi. __________________ Smitty '71 Short Fleetside Spring Valley, Ca.

10-01-2018, 03:04 PM	#4
Barnfind46 Registered User Join Date: Aug 2014 Location: Mena,Arkansas Posts: 485	Re: What kind of gas mileage do you get with your 67-72? 12 to 14 MPG is not out of reach.Keep your tire pressure at the top of the safe usable range for your tires and keep it in good tune and you should do better. I do know that fuel with ethanol tends to drop mileage a bit. Mine is a C-20 with a 327, TH 350 and 3.73 gears. I get about 14 to 15 MPG. __________________ 68' with no bells or whistles unless I add'em.

10-01-2018, 03:11 PM	#5
P7M89MM Registered User Join Date: Apr 2017 Location: Spokane, WA Posts: 101	Re: What kind of gas mileage do you get with your 67-72? 6-7mpgs . ZZ502, built th350, 3200 stall, 3.73 posi. __________________ 71 Cheyenne LWB - RideTech Air, zz502, 20" Torq Thrusts 16 Sierra - Bilstein 6112/5160, 33" Duratracs, Method Race Wheels, GMPP Intake, Borla Exhaust 15 4Runner - Icon Coilovers, 33" Duratracs, Pro Comp Wheels, NFABs 16 Malibu Response TXi

10-01-2018, 03:49 PM	#6
dfwright Registered User Join Date: Jan 2009 Location: San Antonio, Texas Posts: 1,376	Re: What kind of gas mileage do you get with your 67-72? I have stock 350, stock quadrajet, stock TH350 transmission with .308 gears, and I get between high 12 to mid 13 mpg, depending on where and how I'm driving __________________ 1972 C10 LWB, 350/350 Deconstruction began 5/2009, mostly completed restoration, 5/2017

10-01-2018, 04:37 PM	#7
Steeveedee Who Changed This? Join Date: Jan 2013 Location: Simi Valley, CA Posts: 10,932	Re: What kind of gas mileage do you get with your 67-72? Like my sig says, 400/400THM/3.54 axle, factory equipment, except the engine and trans have been rebuilt. I haven't checked it without the travel trailer; when towing that, I get 7 MPG. I recall my FiL telling me it used to get 13 mpg, but we put a 12" taller camper shell on it, so it's going to have dropped because of that. __________________ ~Steven '70 Chevy 3/4T Longhorn CST 402/400/3.56 Custom Camper Simi Valley, CA

10-01-2018, 04:56 PM	#8
RenoKeene Florida Edition Join Date: Oct 2010 Location: Fruitland Park, FL Posts: 4,043	Re: What kind of gas mileage do you get with your 67-72? I'm not much help because I really don't care, I just enjoy. 402 /400 /3.08 posi Attached Images __________________ 70 GMC Short Stepside "Rose"-An American Beauty: Factory 402/TH400, AM/FM, AC, Tilt, Tach, Buckets, Posi, PS, PB, 3-5 Drop, Complete Resto-Rod 67 C-20 Slant Back Wrecker "Mad Max" 67 C-10 Ratrod "Step-N-Wolf" 71 Serro Scotty Sportsman camper "Scotty" 97 LT1 Z28 "The Hornet" Link to more pics of "Rose" http://67-72chevytrucks.com/vboard/a...p?albumid=1684 Check out my "Cheap Tricks" thread and add to it if you can, lots of good info there. http://67-72chevytrucks.com/vboard/s...d.php?t=489394

10-01-2018, 05:08 PM	#9
tdangle Registered User Join Date: Mar 2005 Location: Jurupa Valley, Ca Posts: 1,211	Re: What kind of gas mileage do you get with your 67-72? Around 14 mpg with a stock 350, 200r4 trans and 4.10 gears. This is mostly around town with a little freeway at 70 mixed in. __________________ Terry 1970 Custom Camper/C20 , GM Crate 350/7004R, Dana 60, factory AC

10-01-2018, 06:18 PM	#10
Chris_oz Registered User Join Date: Sep 2018 Location: Newcastle, New South Wales, Australia Posts: 139	Re: What kind of gas mileage do you get with your 67-72? stock 350, 4 speed, 4.57 diff on 8.75r16.5 tyres, if I sit on or under 60, its 15mpg. any faster and it drops to 12mpg. Bone stock in every way, 72k on clock, stock Qjet.

10-01-2018, 06:58 PM	#11
OregonNed Registered User Join Date: Dec 2012 Location: Vancouver, Washington Posts: 1,644	Re: What kind of gas mileage do you get with your 67-72? I get 12 ish with the non-ethanol premium I use. __________________ 1968 Chevrolet C/10 LWB - 327, TH350 - 4/5 Drop

10-01-2018, 07:12 PM	#12
72c20customcamper Registered User Join Date: Jul 2018 Location: Catskill Mountains,NY Posts: 8,915	Re: What kind of gas mileage do you get with your 67-72? Really 10 mpg around town is about the norm for a truck made when gas was 45 cents a gallon. Mine gets 12 on the highway doing 60. And that's in 4200lb box. __________________ Mark 72 c20 custom camper Husky edition, 66 SS396 Chevelle 1964 Hawk, 63 Avanti,62 lark 1969 AMX , 1968 c20 stepside ,85 K20 1977 Suburban sold 68 anniversary.

10-01-2018, 07:19 PM	#13
Andy4639 Old member Join Date: Jan 2002 Location: Liberty, & Garden City S.C. , U.S. Posts: 19,945	Re: What kind of gas mileage do you get with your 67-72? 71 with 2014 LS 6.0 and 4L80-e trans. 4:10 gears get 16-18 running 75-80 MPH with the AC on. Ramp truck might get 12 with 350 and a granny 4 speed in it. No idea what rear end gears are. __________________ 1971 LWB Custom, 6.0LS & 4L80E, Speedhut.com GPS speedometer & gauges with A/C. 20" Boss 338's Grey wheels 4 wheel disc brakes. My Driver Seeing the USA in a 71 Upstate SC GM Truck Club 2013,14 and 2016 Hot Rod Pour Tour http://upstategmtrucks.com/ Get out and drive the truck this summer and have some fun! It sucks not being able to hear! LWB trucks rule, if you don't think so measure your SWB! After talking to tech support at Air Lift I have found out that the kit I need is 60811. Per the measurements I gave them. Ride height of truck inside spring and inside diameter of springs.

10-01-2018, 08:32 PM	#14
Willys47 Registered User Join Date: Dec 2007 Location: Nanaimo B.C. Posts: 604	Re: What kind of gas mileage do you get with your 67-72? 460 / 400 trans / 373 rearend I cant pass a gas station . Attached Images __________________ I was hooked on these trucks since 1982 when I drove my budys fathers 1968 Custum GMC 396 automatic dana 60 rear with a power lock diff what a ride more fun then we will we can ever tell!!

10-01-2018, 09:05 PM	#15
custom10nut Registered User Join Date: Apr 2015 Location: East Tn (In the heart of the Smoky Mtns) Posts: 1,903	Re: What kind of gas mileage do you get with your 67-72? I’m satisfied if I average 13-15 on the highway. I will stop for gas at 200ish miles, but try not to go less than an 1/8th before stopping. If I put a load, or have long hills, and the ol girl drinks like a sailor on shore leave. Doesn’t matter though, she ain’t goin nowhere I run a standard 350/4bbl TH350, and 3.73 diff



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10-01-2018, 09:10 PM	#16
weim55 Registered User Join Date: Jan 2017 Location: Larkspur, Colorado Posts: 916	Re: What kind of gas mileage do you get with your 67-72? SWB fleet 1/2 ton, '99 roller cam 350 9.8 compression w/ mild cam, Edelbrock performer intake and AFB carb, headers, TH400 w/2500 stall, 3.54 rear. 15mpg @ crystal 65mph, 11mpg @ 75mph, 10-12mpg mixed driving. 10mpg pulling the race car on a trailer @ 60 mph. 5000-7500 feet elevation. In my years of engine building I found a typical V8 will get one additional mile per gallon per point of raised compression....... Steve weim55 Colorado Last edited by weim55; 10-01-2018 at 11:12 PM.

10-01-2018, 09:13 PM	#17
special-K Special Order Join Date: Nov 2004 Location: Mt Airy, MD Posts: 85,851	Re: What kind of gas mileage do you get with your 67-72? I don't want to talk about it! It sucks now, but used to get a steady 12.5 no matter how I drove, hiway or country roads. It's been more like 10 in more recent years. I put different heads on a couple years ago and now it seems to be just under 10.... '72 K2500 350/TH350/4.10 with 285/75-16 Goodyear Duratracs __________________ "BUILDING A BETTER WAY TO SERVE THE USA"......67/72......"The New Breed" GMC '67 C1500 Wideside Super Custom SWB: 327/M22/3.42 posi.........."The '67" (project) GMC '72 K2500 Wideside Sierra Custom Camper: 350/TH350/4.10 Power-Lok..."The '72" (rolling) Tim "Don't call me a redneck. I'm a rough cut country gentleman" R.I.P. ~ East Side Low Life ~ El Jay ~ 72BLUZ ~ Fasteddie69 ~ Ron586 ~ 67ChevyRedneck ~ Grumpy Old Man ~

10-01-2018, 09:23 PM	#18
gvw5400 Registered User Join Date: May 2013 Location: Colorado Rocky Mountains Posts: 263	Re: What kind of gas mileage do you get with your 67-72? LWB fleet 1/2 ton, 350 300 h.p. cam, Edelbrock performer RPM, 750 cfm AFB, ramhorns ,2.5 true dual exhaust, CH 465 4 spd, 3.73 axle ratio. 15.25 mpg @ 65-70 mph 5000' to 9000' elevation. All the Best, Dirk

10-01-2018, 09:28 PM	#19
Zone47 Registered User Join Date: Sep 2014 Location: Richfield, Oh Posts: 112	Re: What kind of gas mileage do you get with your 67-72? Hmmm! I guess I'll just some high compression heads, an air gap performer, a 280/460 cam and not worry about it. It sounds like it will probably at least still get 10 mpg with all that, but at least run better.

10-01-2018, 09:30 PM	#20
Fbks_Cruiser Senior Member Join Date: Apr 2016 Location: Fairbanks, AK Posts: 344	Re: What kind of gas mileage do you get with your 67-72? 72 K2500. 350/TH 350, 4:10, 235/85 R16 tires, HEI, Eldebrock 1406 carb, RV cam. 10-11 mph mixed highway and town driving using gps since my speedo is off by about 10%. __________________ 1972 GMC K2500 Super Custom Matt Last edited by Fbks_Cruiser; 10-01-2018 at 09:36 PM.

10-01-2018, 09:44 PM	#21
lutronjim Registered User Join Date: Dec 2013 Location: Dunwoody,Ga Posts: 443	Re: What kind of gas mileage do you get with your 67-72? My 70 C10 with 307 4 barrel when new got 16mpg on highway when driven for mileage. I upgraded to LC9 with 65E and now driven for mileage on highway gets 21.

10-01-2018, 10:35 PM	#23
poway Registered User Join Date: Jun 2012 Location: Poway, CA Posts: 119	Re: What kind of gas mileage do you get with your 67-72? 1968 GMC half ton fenderside. Stock 250 six, turbo 400 trans, 3.54 rear end. My daily driver for about 2 years. 13-15 mpg.

10-01-2018, 11:17 PM	#25
weim55 Registered User Join Date: Jan 2017 Location: Larkspur, Colorado Posts: 916	Re: What kind of gas mileage do you get with your 67-72? Like to hear from some six-cylinder people.......

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