6 cyl MPG - The 1947 - Present Chevrolet & GMC Truck Message Board Network

rio · 04-04-2008, 11:26 PM

How Many MPG does a 250 6 cyl get. and How much less with 4-BBL INTAKE MANIFOLD?

Bus Ted Knuckle · 04-05-2008, 12:00 AM

I'd venture to say anywhere from 8-15 with stock or 4 barrel intake. Too many variables to really nail it down. What kind of 4 barrel are you using? If it is a q-jet, your not going to harldly even open up the secondaries with a worn out 250.

68gmsee · 04-05-2008, 12:34 AM

I just got my 68 GMC road worthy again week before last. Filled it up and drove it mostly on the highway between 55 and 60 mph. I was surprised that I got 18 mpg on it. I was expecting aroun 14-15 like my 69 Chevy used to get.

Here are the truck's stats: No A/C, 250 six bored .030 over with a 3 speed saginaw and 3.73 rear end, 235/75R/15 tires. I put a rebuilt single barrel Rochester manual choke carb, new style solid state voltage regulator.

It has plenty of zip for what I need it for and I'll be checking mpg on it for a while to see if it's going to vary much.

rio · 04-05-2008, 03:05 AM

anyone?

MXmaniac · 04-05-2008, 06:53 AM

I have a 292 with a one barrel Rochester Monojet carb and a granny low four-speed, with very low gears in the rear end(4.56 or something). Last time I filled up I got 10.8.

pritch · 04-05-2008, 07:25 AM

Nobody ever believes me, but get around 20 in my Panel. But it has a 230 and a 1 BBL. I'll miss that milage when I change to a bigger motor.

MXmaniac · 04-05-2008, 07:29 AM

Wow, what transmission and gears do you have?

Brad · 04-05-2008, 08:59 AM

See below. We've answered this question for you before...

Longhorn Man · 04-05-2008, 01:57 PM

a 230 in the panel?

shifty · 04-05-2008, 06:50 PM

Brad - you forgot the link

I was thinking I had deja vu, now I just wonder how many times we're going to answer the same question this month.

Longhorn Man · 04-05-2008, 10:15 PM

I thought its come up a few times... wasn't sure if it was the same guy.

67ChevyRedneck · 04-05-2008, 10:31 PM

Meh, I'll play anyway... Back when the old girl was a 250/3 speed manual/3.73... I got around 10-11 mpg.

68gmsee · 04-05-2008, 10:58 PM

Yeah, we've been through this one every few months.

Quote:

Originally Posted by 67ChevyRedneck

Meh, I'll play anyway... Back when the old girl was a 250/3 speed manual/3.73... I got around 10-11 mpg.

I wonder what's different on mine. Maybe it's cause I didn't go much over 60 mph. Is this all in town driving?

67ChevyRedneck · 04-05-2008, 11:22 PM

Quote:

Originally Posted by 68gmsee

Yeah, we've been through this one every few months.

I wonder what's different on mine. Maybe it's cause I didn't go much over 60 mph. Is this all in town driving?

Make sure your odometer is reading right. For a stock 3 speed, 18 sounds pretty high...

I guess you could consider it that. I lived in the sticks. Mostly drove 50-60 mph everywhere I went. Truck probably could have used a tune up and a new carb. If I had put some money in it I might have gotten 12 or 13. I can only see getting 18mpg with a 5 speed/3.73 rear.

shifty · 04-05-2008, 11:38 PM

i'll say it again, even though i have answered multiple times recently - with 3.73 gears, an L-250 with new single-bbl monojet carb, 3-on-the-tree with my muncie 3spd (which is in great shape and for sale), i was getting around 8-12mpg.

i can't imagine you'll get better than 12mpg with stock rear end and a 4bbl carb.

68gmsee · 04-06-2008, 02:06 AM

Quote:

Originally Posted by 67ChevyRedneck

Make sure your odometer is reading right. For a stock 3 speed, 18 sounds pretty high...
.

I checked the speedometer with one of my other vehicles at different speeds-40, 50, and 60. Mine was showing about 2 mph slower. I'm also going to check it with my new Trailblazer since it has the orginal tires on it.

For sure I was surprised since my 69 Chevy got no more than 14 on the highway with the old 250 three speed. This GMC, however, has only 28K original miles on it. I bored it over .030 because the rings were gummed up from sitting and while I had it open, decided to do it.

zeeklu · 04-06-2008, 02:21 AM

I get about 12 with a K10 with a 292 headers,Clifford water heated manifold and a Holley 390CFM 4 BBL. Chris

pritch · 04-06-2008, 06:38 AM

Quote:

Originally Posted by Longhorn Man

a 230 in the panel?

It's wierd, but that's what's in it. At some point, some PO stuck it in. I didn't realize it until I had to change a piston. I sure don't win many races.

I never have bothered to find out what gears I have, 'cause the entire drivetrain is going away during the upcoming frame-off. I took it out today for the first time this spring-drove about a hundred miles, used just over a quarter tank of gas. I believe that my speedo is fairly close. There is a real bad turn on my route that has one of those 'Your Speed Is:' radar signs and It read within a couple of MPH of what the speedo said.

ed2552 · 04-06-2008, 07:11 AM

I hate to brag, but my 98 Tahoe gets 18 with the A/C on and pulling a 2,000 Lb trailer all over heck with a lawnmower and crap, and it has the 350, and a 4L60E, and it is not THAT much better aerodynamically than these trucks, but it does have OD and Fuel Injection, but does it make it that much better than a I6 truck? Doesn't seem like it should, but aparrently does.

Longhorn Man · 04-06-2008, 05:40 PM

ed, late models have all kinds of things done to reduce friction, they are considerably more aerodynamic than you think.
Pritch... that is crazy huh? I bet it is pretty gutless huh?

ed2552 · 04-06-2008, 07:58 PM

Whatever you say, your holyness

72gmcworker · 04-06-2008, 08:22 PM

My stock '79 chev with a fresh 250, single barrel, 350 tranny was getting about 21 miles/Imperial gallon....nearly 18 a US gallon in mixed 50-60mph driving.

The '72 with 350 q-jet, 350 tranny was getting about 13miles/Imperial or 11 per US gallon.
GPS confirmed my speedo inaccuracies and so accounted for.
All with synthetic oil including the tranny of the '79

Oh yah we are now paying about $4.59 for a US gallon for 91premium here
or $1.20 per litre
Regular is about $1.12/litre $4.26/gallon
Diesel around $4.60/gallon

OUCH

ed2552 · 04-06-2008, 08:27 PM

i thought our diesel was bad at $3.95 out here in the sticks. Some of the semi drivers can't fill their trucks up all the way b/c their credit cards stop at $500.

Longhorn Man · 04-06-2008, 09:49 PM

a lot of that fuel cost is your local/state/fed taxes.

68gmsee · 04-06-2008, 11:56 PM

Quote:

Originally Posted by ed2552

I hate to brag, but my 98 Tahoe gets 18 with the A/C on and pulling a 2,000 Lb trailer all over heck with a lawnmower and crap, and it has the 350, and a 4L60E....

Yep, I can believe it. My old departed 96 Tahoe with the same setup would consistently average 21 mpg. One time driving to west Texas with a tailwind I got about 22 mpg. The injectors started messing up at around 200K and mileage dropped to 18. Loved that suv.

04-04-2008, 11:26 PM	#1
rio Junior Member Join Date: Sep 2007 Location: Brenham,TX Posts: 571	6 cyl MPG How Many MPG does a 250 6 cyl get. and How much less with 4-BBL INTAKE MANIFOLD?

04-05-2008, 12:00 AM	#2
Bus Ted Knuckle Son of a gun Join Date: Jan 2007 Location: Hot Springs, Arkansas Posts: 1,636	Re: 6 cyl MPG I'd venture to say anywhere from 8-15 with stock or 4 barrel intake. Too many variables to really nail it down. What kind of 4 barrel are you using? If it is a q-jet, your not going to harldly even open up the secondaries with a worn out 250. __________________ Bill BEATERS ARE NEATER

04-05-2008, 12:34 AM	#3
68gmsee Active Member Join Date: Jul 2007 Location: Centrally located between Houston, Austin and Waco. BCS area. Posts: 7,947	Re: 6 cyl MPG I just got my 68 GMC road worthy again week before last. Filled it up and drove it mostly on the highway between 55 and 60 mph. I was surprised that I got 18 mpg on it. I was expecting aroun 14-15 like my 69 Chevy used to get. Here are the truck's stats: No A/C, 250 six bored .030 over with a 3 speed saginaw and 3.73 rear end, 235/75R/15 tires. I put a rebuilt single barrel Rochester manual choke carb, new style solid state voltage regulator. It has plenty of zip for what I need it for and I'll be checking mpg on it for a while to see if it's going to vary much.

04-05-2008, 03:05 AM	#4
rio Junior Member Join Date: Sep 2007 Location: Brenham,TX Posts: 571	Re: 6 cyl MPG anyone?

04-05-2008, 06:53 AM	#5
MXmaniac Registered User Join Date: Jan 2007 Location: Denton, Texas Posts: 356	Re: 6 cyl MPG I have a 292 with a one barrel Rochester Monojet carb and a granny low four-speed, with very low gears in the rear end(4.56 or something). Last time I filled up I got 10.8. __________________ Andrew '69 C-20(292, 4-speed) Retired Daily Driver '64 C-10(250, 3-speed) Fixerupper '97 F*rd Mustang GT(4.6L, 5-speed) Daily Driver If I only wanted two pedals I'd have bought a bicycle.

04-05-2008, 07:25 AM	#6
pritch Registered User Join Date: Mar 2004 Location: Hoytsville, Utah Posts: 3,365	Re: 6 cyl MPG Nobody ever believes me, but get around 20 in my Panel. But it has a 230 and a 1 BBL. I'll miss that milage when I change to a bigger motor. __________________ '68 Panel Project Boogie Chillin' '68 C-10 Ol' Green

04-05-2008, 07:29 AM	#7
MXmaniac Registered User Join Date: Jan 2007 Location: Denton, Texas Posts: 356	Re: 6 cyl MPG Wow, what transmission and gears do you have? __________________ Andrew '69 C-20(292, 4-speed) Retired Daily Driver '64 C-10(250, 3-speed) Fixerupper '97 F*rd Mustang GT(4.6L, 5-speed) Daily Driver If I only wanted two pedals I'd have bought a bicycle.

04-05-2008, 08:59 AM	#8
Brad Out of the carpool lane. Join Date: Jan 2000 Location: Clark Co, WA Posts: 5,673	Re: 6 cyl MPG See below. We've answered this question for you before... __________________ 1968 C-10 SWB, 5.7 Vortec/700R4/3.73 posi, Torch Red 1968 Camaro, 250/Powerglide, all original (No, I'm not gonna drop a 350 in it!...Jeez!) 2000 Honda VFR in the faster yellow! 2008 Husqvarna TE-610 1967 C-10 SWB 'Six Appeal'-Gone but not forgotten...

04-05-2008, 01:57 PM	#9
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	Re: 6 cyl MPG a 230 in the panel?

04-05-2008, 06:50 PM	#10
shifty Questionable Join Date: Mar 2005 Location: Atlanta Posts: 13,376	Re: 6 cyl MPG Brad - you forgot the link I was thinking I had deja vu, now I just wonder how many times we're going to answer the same question this month. __________________ If I've got anything up for grabs, it'll be here: 7-hole gauge cluster for a 67-72 p/u FREE (link) I can't check the forum daily. If I don't reply to you within 24 hours, drop me a PM! I'm (hopefully) still alive and will reply faster to a PM.

04-05-2008, 10:15 PM	#11
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	Re: 6 cyl MPG I thought its come up a few times... wasn't sure if it was the same guy.

04-05-2008, 10:31 PM	#12
67ChevyRedneck Hittin E-Z Street on Mud Tires Join Date: Nov 2004 Location: Greenville, SC Posts: 23,090	Re: 6 cyl MPG Meh, I'll play anyway... Back when the old girl was a 250/3 speed manual/3.73... I got around 10-11 mpg. __________________ Jesse James 1967 C10 SWB Stepside: 350/700R4/3.73 1965 Ford Mustang: 289/T5-5spd/3.25 Trac-Loc 1968 Pontiac Firebird: Project Fire Chicken! 2015 Silverado Double Cab 5.3L Z71 2001 Jeep Wrangler Sport 4.0L 5spd 2020 Chevrolet Equinox Premium 2.0L Turbo 2011 Mustang V6 ~ Wife's ride American Born, Country by the Grace of God 1967 CST Shop Truck Rebuild! My 1967 C-10 Build Thread My Vintage Air A/C Install Project "On a Dime" Trying my hand at Home Renovation! 1965 Mustang Modifications!

04-05-2008, 11:38 PM	#15
shifty Questionable Join Date: Mar 2005 Location: Atlanta Posts: 13,376	Re: 6 cyl MPG i'll say it again, even though i have answered multiple times recently - with 3.73 gears, an L-250 with new single-bbl monojet carb, 3-on-the-tree with my muncie 3spd (which is in great shape and for sale), i was getting around 8-12mpg. i can't imagine you'll get better than 12mpg with stock rear end and a 4bbl carb. __________________ If I've got anything up for grabs, it'll be here: 7-hole gauge cluster for a 67-72 p/u FREE (link) I can't check the forum daily. If I don't reply to you within 24 hours, drop me a PM! I'm (hopefully) still alive and will reply faster to a PM.

04-06-2008, 02:21 AM	#17
zeeklu Registered User Join Date: Dec 1999 Location: Northwest NJ Posts: 746	Re: 6 cyl MPG I get about 12 with a K10 with a 292 headers,Clifford water heated manifold and a Holley 390CFM 4 BBL. Chris

04-06-2008, 07:11 AM	#19
ed2552 Registered User Join Date: Jan 2007 Location: Charles City IA Posts: 1,626	Re: 6 cyl MPG I hate to brag, but my 98 Tahoe gets 18 with the A/C on and pulling a 2,000 Lb trailer all over heck with a lawnmower and crap, and it has the 350, and a 4L60E, and it is not THAT much better aerodynamically than these trucks, but it does have OD and Fuel Injection, but does it make it that much better than a I6 truck? Doesn't seem like it should, but aparrently does. __________________ '67 C20, Under the Knife!, LWB, Eaton HO-52, Rear Coil Springs 72' GMC C2500, 350, TH400(?), Dana 60 '67 K10 4-spd., 305, SM465, Dana 44, 12 Bolt, RUST! '65 C60 292, 4 spd, 2 spd Rearend, 15' Grain Box, MINT! 09 Yukon Denali 82k Miles 6.2L/6A



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04-06-2008, 05:40 PM	#20
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	Re: 6 cyl MPG ed, late models have all kinds of things done to reduce friction, they are considerably more aerodynamic than you think. Pritch... that is crazy huh? I bet it is pretty gutless huh?

04-06-2008, 07:58 PM	#21
ed2552 Registered User Join Date: Jan 2007 Location: Charles City IA Posts: 1,626	Re: 6 cyl MPG Whatever you say, your holyness __________________ '67 C20, Under the Knife!, LWB, Eaton HO-52, Rear Coil Springs 72' GMC C2500, 350, TH400(?), Dana 60 '67 K10 4-spd., 305, SM465, Dana 44, 12 Bolt, RUST! '65 C60 292, 4 spd, 2 spd Rearend, 15' Grain Box, MINT! 09 Yukon Denali 82k Miles 6.2L/6A Last edited by ed2552; 04-06-2008 at 07:59 PM.

04-06-2008, 08:22 PM	#22
72gmcworker Registered User Join Date: May 2006 Location: North x Northwest BC Posts: 62	Re: 6 cyl MPG My stock '79 chev with a fresh 250, single barrel, 350 tranny was getting about 21 miles/Imperial gallon....nearly 18 a US gallon in mixed 50-60mph driving. The '72 with 350 q-jet, 350 tranny was getting about 13miles/Imperial or 11 per US gallon. GPS confirmed my speedo inaccuracies and so accounted for. All with synthetic oil including the tranny of the '79 Oh yah we are now paying about $4.59 for a US gallon for 91premium here or $1.20 per litre Regular is about $1.12/litre $4.26/gallon Diesel around $4.60/gallon OUCH __________________ '70 Pontiac Firebird Esprit '72 GMC 2500 '90 GMC V1500 '94 Dodge Cummins 2500 '02 Dodge 2500 Quad Cab Long Box 4x4 gasser Last edited by 72gmcworker; 04-06-2008 at 08:27 PM.

04-06-2008, 08:27 PM	#23
ed2552 Registered User Join Date: Jan 2007 Location: Charles City IA Posts: 1,626	Re: 6 cyl MPG i thought our diesel was bad at $3.95 out here in the sticks. Some of the semi drivers can't fill their trucks up all the way b/c their credit cards stop at $500. __________________ '67 C20, Under the Knife!, LWB, Eaton HO-52, Rear Coil Springs 72' GMC C2500, 350, TH400(?), Dana 60 '67 K10 4-spd., 305, SM465, Dana 44, 12 Bolt, RUST! '65 C60 292, 4 spd, 2 spd Rearend, 15' Grain Box, MINT! 09 Yukon Denali 82k Miles 6.2L/6A

04-06-2008, 09:49 PM	#24
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	Re: 6 cyl MPG a lot of that fuel cost is your local/state/fed taxes.

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