is 10 mpg normal? - Page 2 - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Longhorn Man · 03-17-2009, 03:45 PM

Quote:

Originally Posted by tekno62

the spid just says positraction rr axle

Assuming the info you provided is as it was built originally, (350/TH350) and nothing has been chainged, then it'll be a 3.07 gear out back. That was standard with that eng/trans combo.

tekno62 · 03-17-2009, 06:01 PM

No idea really - I'll jack up the truck toniht and do the wheel spin.

I got this truck to do some camping in so any pointer on upping the mileage would be great.

Quote:

Originally Posted by Longhorn Man

Assuming the info you provided is as it was built originally, (350/TH350) and nothing has been chainged, then it'll be a 3.07 gear out back. That was standard with that eng/trans combo.

heavy70 · 03-18-2009, 08:34 PM

mine gets 8-10 with a 355, 650 DP holley, 4.11's, 350 turbo tranny and that is babying it!!!!

into69z · 03-18-2009, 10:37 PM

well, my truck started as a 350/400 combo with a 4:10 gear....and I thoufgt better just before the gas went to $5.00 + to throw in a 468.....I kept the 400 and found a 3:23 semi-floater 3/4 t rear end....I got about 10mpg with the old set-up and I'm getting about 10mpg with the new set-up-the truck wieghs 4400lbs.......now i'am looking for carbon fiber!!

tekno62 · 03-19-2009, 01:27 PM

whats a semi-floater rearend?
Also having own a rice rocket I can say I love carbon fiber.

fun is doing the 1/4 in 10/11 sec with a 1.3 liter rotory

Quote:

Originally Posted by into69z

well, my truck started as a 350/400 combo with a 4:10 gear....and I thoufgt better just before the gas went to $5.00 + to throw in a 468.....I kept the 400 and found a 3:23 semi-floater 3/4 t rear end....I got about 10mpg with the old set-up and I'm getting about 10mpg with the new set-up-the truck wieghs 4400lbs.......now i'am looking for carbon fiber!!

nrb's70gmc · 03-22-2009, 11:54 PM

my 3/4 ton 2wd gets 8.5 mpg im not sure of the gear ratio but the this truck is a gas pig it has a crate 350,turbo 350---it might have 4 10s because it can beat a corvette of the line lol

67ChevyRedneck · 03-17-2009, 04:33 PM

I have a 350/700R/3.73 and I'm getting a consistent 12.5-ish mpg with all of the "city driving" I do. It see's OD only about 25% of the time. On the highway I can squeeze out 14.5-16mpg, completely dependent on speed. I try to have a light foot, but there may be a few spirited romps per tank

For comparison, my silverado with the 5.3/4l60E/3.73 gets 14/18 under the same conditions.

Here's the average economy I got over quite a few tanks when I first installed the 700R. The 14.36 was a mix of lots of highway and some city, I rarely do highway trips, so I don't have those written down, but I do check them.

12.65
12.46
12.79
12.79
14.36
11.93
12.46
13.01
12.53
11.96

oldblue1968chevy · 03-17-2009, 10:14 PM

wats the easiest cheepaest way to get better mpgs

67ChevyRedneck · 03-17-2009, 10:28 PM

Quote:

Originally Posted by oldblue1968chevy

wats the easiest cheepaest way to get better mpgs

Make sure your engine is tuned up and running 100%. If your truck doesn't already have one, a used 67-72 3.07 rear end will help (assuming you have a non OD transmission and 3.73, 4.11, etc rear axle). And finally, DRIVING HABBITS! Slower take offs and feathering the throttle will go a long way compared to romping the pedal nailing the gas then the brakes from stoplight to stoplight.

72chevyk10 · 03-17-2009, 10:40 PM

somthing must be wrong with my truck

i get 12(depending on which way the wind is going) with 4.10 and a 454 with the edel 750cfm carb.no overdrive...

Longhorn Man · 03-17-2009, 10:44 PM

the only time I ever gave it an honest effort, my longhorn was getting 14.5 on the freeway with 4.10 and non overdrive and a caddy 425 pushing it.
But the cad 425 is known for being somewhat of a decent MPG engine

tekno62 · 03-18-2009, 01:26 PM

any idea on what carb to get - guess I need to do some research on upping the mileage.

look out google here I come

magsnubby · 03-18-2009, 02:58 PM

Both my '71 and '72 long beds (both 350/350 combos,totally stock,not sure of the gear raito ) averaged just a tad over 13 mpg. On the '71 when i dropped in the new engine i added long tube headers, HEI with Summit coil, Edelbrock Performer intake/carb, Accel plug wires and dual exhaust with turbo mufflers. At a steady 65 it would pull down 17 mpg on the freeway.

Quote:

Originally Posted by tekno62

...any idea on what carb to get...

Edelbrock performer 600 cfm electric choke.

http://store.summitracing.com/egnsea...&DDS=1&N=700+0

I used this on on my '71 and was amazed at the difference in mileage and power over the Quadrajet.

piecesparts · 03-18-2009, 03:47 PM

I get around 15 MPG with a 700R4 and a 383 stroker motor. I have a 3.73 set of rear end gears and a somewhat lower profile set of tires.

fnoblitt · 03-18-2009, 03:56 PM

i was getting 10 mpg with the 3.73s, i swapped to 3.07 gears and the mileage went up to 14 , but thats mostly highway driving.

67shortie · 03-18-2009, 04:09 PM

I am averaging 14 with 60% freeway with the new 350 and 700 combo. It's not stock but not too wild either.

I do have my foot in it quite a bit, so when I finaly get the fun factor out of my system it will go up...

as others have said, make sure your engine is in good tune and working properly, and of course keep your foot out of it but that is hard to do sometimes

Gray Ghost · 03-18-2009, 06:03 PM

I got better mileage with a 1406 Edlebrock [elec choke 600 cfm] than my current 1405 manual choke. They are setup for performance while the elec choke models are set up for mileage.

67ChevyRedneck · 03-18-2009, 06:05 PM

Since they seem to be getting praise, I'll add that I also have an edelbrock 1406 elec choke carb sitting on top on my tree fiddy as well

tekno62 · 03-18-2009, 06:32 PM

nice to know. did you all add an Edlebrock manifold or keep the stocker?

67ChevyRedneck · 03-18-2009, 07:22 PM

Quote:

Originally Posted by tekno62

nice to know. did you all add an Edlebrock manifold or keep the stocker?

I have one, but I am currently running it on top of a stocker. I have a stash of "good parts" that I'm saving for my crate engine I hope to get someday...

texanidiot25 · 03-18-2009, 06:33 PM

Q-Jets are very nice on gas if you stay outta them as well. Awesome carb when done right, forget the nay-sayers. If I recall right, stock they flow 650.

Zeke · 03-18-2009, 07:03 PM

I don't know if you can really get an accurate mpg on these trucks, my speedo went out and I replaced it with a new repop and my gas milage went up. Figured out it was off 1 mph for every ten indicated so for every 50 miles driven I got an extra 5 on the odometer to boost my MPG.

tekno62 · 03-18-2009, 09:15 PM

when you average it really doesn't matter if your speedo is off a little. the data is off but we're just looking at the average. over all 10 mpg or 12 mpg I feel we could do better. 15 would be just like my 91 sub 4x4. I would be happy with that.

I know I could spend thousands to save a dime (governments do it all the time) but if there something in the hundreds it maybe worth it in the long run. Also the carb and tranny seems to be an easy updates. once I find out the gear ratio of the rearend then Im set.

Quote:

Originally Posted by Zeke

I don't know if you can really get an accurate mpg on these trucks, my speedo went out and I replaced it with a new repop and my gas milage went up. Figured out it was off 1 mph for every ten indicated so for every 50 miles driven I got an extra 5 on the odometer to boost my MPG.

**americanmusc1e** · 03-19-2009, 08:43 PM

Quote:

Originally Posted by texanidiot25

Q-Jets are very nice on gas if you stay outta them as well. Awesome carb when done right, forget the nay-sayers. If I recall right, stock they flow 650.

750 or 800, usually 750, some BB quadrajets did 800 depending on the size of the primarys

**'68OrangeSunshine** · 03-19-2009, 10:47 PM

I get about 10 MPG in my '71 Jimmy -- V8 350/SM465/NP205, 3.73, 33x 12.50x R15LT, but I don't have a working gas gauge. I try to fill it every 100 miles or so.
On my '68 C/10 Stepside with L6 292, SM465 and 3.73 rear, I get about 12 MPG, but it's built .030-over and has a 500 CFM Edelbrock 1404.

03-18-2009, 08:34 PM	#3
heavy70 Registered User Join Date: Dec 2007 Location: choctaw, oklahoma Posts: 100	Re: is 10 mpg normal? mine gets 8-10 with a 355, 650 DP holley, 4.11's, 350 turbo tranny and that is babying it!!!!

03-18-2009, 10:37 PM	#4
into69z "brand new second-hand" Join Date: Feb 2007 Location: White House, Tennessee Posts: 526	Re: is 10 mpg normal? well, my truck started as a 350/400 combo with a 4:10 gear....and I thoufgt better just before the gas went to $5.00 + to throw in a 468.....I kept the 400 and found a 3:23 semi-floater 3/4 t rear end....I got about 10mpg with the old set-up and I'm getting about 10mpg with the new set-up-the truck wieghs 4400lbs.......now i'am looking for carbon fiber!! __________________ Steve 69 3/4t custom camper tilt,am/fm,speed warning,air gauge,buddy buckets,aux battery, big block,p/s,p/b,a/c 67 Camaro 96 Impala ss-sold 04 hybrid Honda-saving gas for the blue truck!:b69:

03-22-2009, 11:54 PM	#6
nrb's70gmc Registered User Join Date: Sep 2008 Location: magalia,ca Posts: 366	Re: is 10 mpg normal? my 3/4 ton 2wd gets 8.5 mpg im not sure of the gear ratio but the this truck is a gas pig it has a crate 350,turbo 350---it might have 4 10s because it can beat a corvette of the line lol __________________ 1970 2wd 3/4 ton- 2004 crate 350 thorley tri-y headers-edelbrock performer eps manifold 600cfm performer carb, crane cams energizer cam,lifters, dual 2.5 magnaflows, mallory HEI, powermaster 140 amp altenator, griffen aluminum radiator.(8 MPG)

03-17-2009, 04:33 PM	#7
67ChevyRedneck Hittin E-Z Street on Mud Tires Join Date: Nov 2004 Location: Greenville, SC Posts: 23,090	Re: is 10 mpg normal? I have a 350/700R/3.73 and I'm getting a consistent 12.5-ish mpg with all of the "city driving" I do. It see's OD only about 25% of the time. On the highway I can squeeze out 14.5-16mpg, completely dependent on speed. I try to have a light foot, but there may be a few spirited romps per tank For comparison, my silverado with the 5.3/4l60E/3.73 gets 14/18 under the same conditions. Here's the average economy I got over quite a few tanks when I first installed the 700R. The 14.36 was a mix of lots of highway and some city, I rarely do highway trips, so I don't have those written down, but I do check them. 12.65 12.46 12.79 12.79 14.36 11.93 12.46 13.01 12.53 11.96 __________________ 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! Last edited by 67ChevyRedneck; 03-17-2009 at 04:38 PM.

03-17-2009, 10:14 PM	#8
oldblue1968chevy Grandpa in the rustmobile... Join Date: Nov 2008 Location: Spokane WA/Viola TN Posts: 11,422	Re: is 10 mpg normal? wats the easiest cheepaest way to get better mpgs __________________ John Goose-1968 C10 355,9.32-1CR, Vortec Heads ,262 voodoo, 3.73:1 3OTT (HS ride/beater/farm truck) http://67-72chevytrucks.com/vboard/s...d.php?t=317684 Grams 53-1953 Chevrolet Belair http://67-72chevytrucks.com/vboard/s...=1#post4327784 1969 Chevy C10 Shortbed 4.5/6?" Frame off resto http://67-72chevytrucks.com/vboard/s...d.php?t=548136 1999 Toyota Tacoma 4x4

03-17-2009, 10:44 PM	#11
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	Re: is 10 mpg normal? the only time I ever gave it an honest effort, my longhorn was getting 14.5 on the freeway with 4.10 and non overdrive and a caddy 425 pushing it. But the cad 425 is known for being somewhat of a decent MPG engine

03-18-2009, 01:26 PM	#12
tekno62 Registered User Join Date: Nov 2008 Location: San Jose Ca Posts: 265	Re: is 10 mpg normal? any idea on what carb to get - guess I need to do some research on upping the mileage. look out google here I come

03-18-2009, 03:47 PM	#14
piecesparts Parts and more parts Join Date: Nov 2003 Location: Lebo, Kansas (middle of nowhere Posts: 6,821	Re: is 10 mpg normal? I get around 15 MPG with a 700R4 and a 383 stroker motor. I have a 3.73 set of rear end gears and a somewhat lower profile set of tires. Last edited by piecesparts; 03-18-2009 at 03:48 PM.

03-18-2009, 03:56 PM	#15
fnoblitt Registered User Join Date: Mar 2002 Location: southern calif.,usa Posts: 200	Re: is 10 mpg normal? i was getting 10 mpg with the 3.73s, i swapped to 3.07 gears and the mileage went up to 14 , but thats mostly highway driving. __________________ 70 c10 stepside ,350v8, m-20 4 speed

03-18-2009, 04:09 PM	#16
67shortie Green club Join Date: May 2002 Location: Central CA Posts: 1,059	Re: is 10 mpg normal? I am averaging 14 with 60% freeway with the new 350 and 700 combo. It's not stock but not too wild either. I do have my foot in it quite a bit, so when I finaly get the fun factor out of my system it will go up... as others have said, make sure your engine is in good tune and working properly, and of course keep your foot out of it but that is hard to do sometimes __________________ 71 short/fleet ECE 4/6 drop, LQ4/700r4/3.42 gears 70 SS396 Chevelle 427/200-4R/3.73posi 61 Lincoln Continental, black on black Son you are going to drive me to drinkin if you don't stop drivin that hot rod lincoln

03-18-2009, 06:03 PM	#17
Gray Ghost Senior Member Join Date: Sep 2004 Location: Terrell, TX Posts: 1,967	Re: is 10 mpg normal? I got better mileage with a 1406 Edlebrock [elec choke 600 cfm] than my current 1405 manual choke. They are setup for performance while the elec choke models are set up for mileage. __________________ Kelly '05 GMC Sierra SLE Z71 Bone stock except for new bed rail caps.

03-18-2009, 06:05 PM	#18
67ChevyRedneck Hittin E-Z Street on Mud Tires Join Date: Nov 2004 Location: Greenville, SC Posts: 23,090	Re: is 10 mpg normal? Since they seem to be getting praise, I'll add that I also have an edelbrock 1406 elec choke carb sitting on top on my tree fiddy as well __________________ 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!

03-18-2009, 06:32 PM	#19
tekno62 Registered User Join Date: Nov 2008 Location: San Jose Ca Posts: 265	Re: is 10 mpg normal? nice to know. did you all add an Edlebrock manifold or keep the stocker?

03-18-2009, 06:33 PM	#21
texanidiot25 Eat My Rust Join Date: Jan 2007 Location: Cypress, Texas Posts: 3,362	Re: is 10 mpg normal? Q-Jets are very nice on gas if you stay outta them as well. Awesome carb when done right, forget the nay-sayers. If I recall right, stock they flow 650. Last edited by texanidiot25; 03-18-2009 at 06:35 PM.

03-18-2009, 07:03 PM	#22
Zeke Active Member Join Date: Jun 2002 Location: L.A. Lower Alabama Posts: 453	Re: is 10 mpg normal? I don't know if you can really get an accurate mpg on these trucks, my speedo went out and I replaced it with a new repop and my gas milage went up. Figured out it was off 1 mph for every ten indicated so for every 50 miles driven I got an extra 5 on the odometer to boost my MPG. __________________ 1969 C10 350 3spd 1995 GMC 3500 XC 350 dually When Thomas Edison worked late into the night on the electric light, he had to do it by gas lamp or candle. I'm sure it made the work seem that much more urgent. George Carlin



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03-19-2009, 10:47 PM	#25
'68OrangeSunshine Senior Member Join Date: Feb 2002 Location: Tucson, AZ USA Posts: 7,107	Re: is 10 mpg normal? I get about 10 MPG in my '71 Jimmy -- V8 350/SM465/NP205, 3.73, 33x 12.50x R15LT, but I don't have a working gas gauge. I try to fill it every 100 miles or so. On my '68 C/10 Stepside with L6 292, SM465 and 3.73 rear, I get about 12 MPG, but it's built .030-over and has a 500 CFM Edelbrock 1404. __________________ Every 25 years I like to rebuild that 292, whether it needs it or not.

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