improving fuel milege??? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

ocbaud · 02-09-2007, 09:55 AM

anyways to help with fuel economy in my truck???

any little bit help, it averages about 11mpg right now.

here are the specs on it

355ci
10:1 Compression Ratio
Holley systemaxII alum. heads
Comp cams 270H magnum
Holley street dominator intake
MSD Pro-Billet distributor #8361
MSD Blaster2 Coil
MSD 6AL Ignition box
Edelbrock Thunder Series 650cfm AVS carb
Aeromotive Billet Fuel Pressure Regulator
shortie headers
K&N 4" Open Element air filter

3.73 gears
Eaton Limited-Slip Diff.

Th350c transmission
2800 stall torque conveter
B&M Stacked plate trans cooler
trans-go transpack

i'm thinking a new carb, but the one i want is SO expensive

(650cfm mighty demon)

and i plan on getting a built up 700r4, but those are expensive too and the torque converters are expensive for them too!

Slonaker · 02-09-2007, 10:01 AM

It sounds like a built up 700R4 is the next step. That will be expensive, of course, which is why I don't have one.

I doubt you'll do much better than that with a TH350 and 3.73 gears. I'm surprised that your mileage is that high.

Slonaker

ocbaud · 02-09-2007, 10:15 AM

Quote:

Originally Posted by Slonaker

It sounds like a built up 700R4 is the next step. That will be expensive, of course, which is why I don't have one.

I doubt you'll do much better than that with a TH350 and 3.73 gears. I'm surprised that your mileage is that high.

Slonaker

i was telling angie i was gonna spend our tax return on a new tranny and a blower for my truck. she just laughed at me

84slopwaggin · 02-09-2007, 01:38 PM

Man you should just sell me that truck and get you a Nissan Hardbody for increased fuel economy

.

**Captkaos** · 02-09-2007, 01:50 PM

Putting a Demon on there would be going backwards in gas mileage in my experience. For mileage a spreadbore would be a better choice.

ocbaud · 02-09-2007, 01:58 PM

Quote:

Originally Posted by Captkaos

Putting a Demon on there would be going backwards in gas mileage in my experience. For mileage a spreadbore would be a better choice.

ah i know, but it'll have MORE POWER!!!

its not like i drive the truck everyday

CLASSIC87' · 02-09-2007, 02:38 PM

Quote:

Originally Posted by ocbaud

ah i know, but it'll have MORE POWER!!!

its not like i drive the truck everyday

MORE POWER usually equals MORE GAS...
If you don't drive it everyday... then don't worry about the gas mileage

Prerunner1982 · 02-09-2007, 02:45 PM

I think fuel injection would be a good step for a bit of increased MPG and performance as well. Then a built 700r4....

ocbaud · 02-09-2007, 02:54 PM

Quote:

Originally Posted by Prerunner1982

I think fuel injection would be a good step for a bit of increased MPG and performance as well. Then a built 700r4....

if i was gonna spend that much money for fuel injection, i would much rather it go towards a blower

SSC's76 · 02-09-2007, 03:08 PM

Quote:

Originally Posted by ocbaud

if i was gonna spend that much money for fuel injection, i would much rather it go towards a blower

Actually the Blower would increase your fuel economy as long as you drive like a granny. Only problem is that 10:1 compression ratio needs to drop a few points before the blower goes on.

82c10 · 02-09-2007, 03:50 PM

700r4's suck, listen, if you are wanting to do that get a gearvendor's overdrive

Malo83 · 02-09-2007, 04:02 PM

It's a tradeoff, with all those go fast goodies on the engine,10.1 compr. don't think it's gonna happen, since it's not your DD I wouldn't worry about it, cake is good but sometimes you can't eat it.

slugish · 02-09-2007, 10:17 PM

Consider putting a lower # gear ratio in ,like a 3.42 or 3.23. With your engine you would still have a good low end & be able to cruise without engine souding like its going to blow up. Ihad a 3.73 in my truck with the 3 speed turbo trans. but took it out . 350 / 3.73 is agood combo if you run mostly on the strip.

slugish · 02-09-2007, 10:18 PM

What is a gearvender overdrive. Im interested.

Slonaker · 02-09-2007, 10:57 PM

Quote:

Originally Posted by slugish

What is a gearvender overdrive. Im interested.

For wgat one will cost, you could buy another truck. I'd love to have one, but not for that kind of money.

http://www.gearvendors.com/

Slonaker

79Silv4x4 · 02-09-2007, 11:33 PM

Dude, you've been around long enough to know the answer to this question.

If you are getting a true 11mpg with current setup do a happy dance

.

These bricks are not gonna get 18mpg despite the constant claims we all see here.

bulky · 02-09-2007, 11:40 PM

You could always do the "Poor Man's" Gear Vendor..... This is an old "DoodleBug" for sale up here locally. It has a 4 speed attached to a 3 speed.

ocbaud · 02-09-2007, 11:52 PM

Quote:

Originally Posted by 79Silv4x4

Dude, you've been around long enough to know the answer to this question.

If you are getting a true 11mpg with current setup do a happy dance

.

These bricks are not gonna get 18mpg despite the constant claims we all see here.

i know

i just wanted to post some more in here

yeah its about 11mpg a little less on the highway. not like it matters, the mustang gets 20mpg so i'm fine with that. the trucks had maybe 300 miles put on her in the past year

so i'm gonna end up buying the speed demon 650 carb, which means i'll have that 650 edelbrock and accessories for sale soon

if anyone wanted to know

grinch4om · 02-10-2007, 08:23 AM

do the 700 tranny, I have one behind my big block witha 2500 stall(lock up) and it does 16-17 on highway at 65mph, of course thats no wind and good baro pressure yadda yadda....

**N2TRUX** · 02-10-2007, 12:07 PM

Screw mpg, just focus an ET and forget the rest...

82c10 · 02-10-2007, 01:12 PM

Quote:

Originally Posted by N2TRUX

Screw mpg, just focus an ET and forget the rest...

it's slow

boatpuller · 02-10-2007, 01:13 PM

i agee,if you want mpg....get a datsun.

ocbaud · 02-10-2007, 01:37 PM

Quote:

Originally Posted by 82c10

it's slow

haha its faster than my mustang.

82c10 · 02-10-2007, 02:07 PM

Quote:

Originally Posted by ocbaud

haha its faster than my mustang.

what does the truck run, if i remember the stang is 13.80x

ocbaud · 02-10-2007, 02:46 PM

Quote:

Originally Posted by 82c10

what does the truck run, if i remember the stang is 13.80x

the mustang ran a best of 14.2 @ 100mph

the truck ran a best of 15.09 @ 90mph with 2 flat cam lobes, open rear end with 2.73 gears and an untuned carb(which it still is)

02-09-2007, 09:55 AM	#1
ocbaud Garage Queen Material Join Date: Oct 2002 Location: USA Posts: 4,129	improving fuel milege??? anyways to help with fuel economy in my truck??? any little bit help, it averages about 11mpg right now. here are the specs on it 355ci 10:1 Compression Ratio Holley systemaxII alum. heads Comp cams 270H magnum Holley street dominator intake MSD Pro-Billet distributor #8361 MSD Blaster2 Coil MSD 6AL Ignition box Edelbrock Thunder Series 650cfm AVS carb Aeromotive Billet Fuel Pressure Regulator shortie headers K&N 4" Open Element air filter 3.73 gears Eaton Limited-Slip Diff. Th350c transmission 2800 stall torque conveter B&M Stacked plate trans cooler trans-go transpack i'm thinking a new carb, but the one i want is SO expensive (650cfm mighty demon) and i plan on getting a built up 700r4, but those are expensive too and the torque converters are expensive for them too!

02-09-2007, 10:01 AM	#2
Slonaker Insert Witty Text Here Join Date: Oct 2002 Location: San Antonio, TX Posts: 3,415	Re: improving fuel milege??? It sounds like a built up 700R4 is the next step. That will be expensive, of course, which is why I don't have one. I doubt you'll do much better than that with a TH350 and 3.73 gears. I'm surprised that your mileage is that high. Slonaker __________________ '86 Chevy C10 (Sold 04/19/13 ) Stock '01 Silverado

02-09-2007, 01:38 PM	#4
84slopwaggin Registered User Join Date: Apr 2005 Location: Ar Posts: 558	Re: improving fuel milege??? Man you should just sell me that truck and get you a Nissan Hardbody for increased fuel economy .

02-09-2007, 01:50 PM	#5
Captkaos www.73-87chevytrucks.com Join Date: Dec 1999 Location: Birmingham, AL Posts: 6,935	Re: improving fuel milege??? Putting a Demon on there would be going backwards in gas mileage in my experience. For mileage a spreadbore would be a better choice. __________________ Chris Lucas 1973 Chevy C-10 1978 GMC Jimmy (2WD) - SOLD 1987 R10 twin turbo LS 1991 R3500 SRW CrewCab 1985 K5 diesel swapped project 1989 K5 2WD conversion w/ Vette susp Project Captkaos Customs 73-87chevytrucks.com

02-09-2007, 03:50 PM	#11
82c10 needin' money Join Date: May 2005 Location: Chickasha, Oklahoma Posts: 1,106	Re: improving fuel milege??? 700r4's suck, listen, if you are wanting to do that get a gearvendor's overdrive __________________ *SWB Stands for Short Wide Bed*

02-09-2007, 02:45 PM	#8
Prerunner1982 Registered User Join Date: Oct 2002 Location: Edmond, OK Posts: 5,904	Re: improving fuel milege??? I think fuel injection would be a good step for a bit of increased MPG and performance as well. Then a built 700r4.... __________________ Jon 1982 Chevy Silverado 350/th350.... RETIRED 1993 Jeep XJ 2 door(Cherokee) 4wd 4.0ltr/AX-15 (5spd)/NP231 .... Oklahoma Roll Call

02-09-2007, 04:02 PM	#12
Malo83 Cruzzzn' Vet Join Date: Jan 2005 Location: Porterville,Ca. Posts: 1,918	Re: improving fuel milege??? It's a tradeoff, with all those go fast goodies on the engine,10.1 compr. don't think it's gonna happen, since it's not your DD I wouldn't worry about it, cake is good but sometimes you can't eat it.

02-09-2007, 10:17 PM	#13
slugish Slugish Join Date: Jan 2005 Location: Earlysville, Va. Posts: 1,024	Re: improving fuel milege??? Consider putting a lower # gear ratio in ,like a 3.42 or 3.23. With your engine you would still have a good low end & be able to cruise without engine souding like its going to blow up. Ihad a 3.73 in my truck with the 3 speed turbo trans. but took it out . 350 / 3.73 is agood combo if you run mostly on the strip.

02-09-2007, 10:18 PM	#14
slugish Slugish Join Date: Jan 2005 Location: Earlysville, Va. Posts: 1,024	Re: improving fuel milege??? What is a gearvender overdrive. Im interested.

02-09-2007, 11:33 PM	#16
79Silv4x4 Workaholic Join Date: Oct 2002 Location: Katy, TX Posts: 1,589	Re: improving fuel milege??? Dude, you've been around long enough to know the answer to this question. If you are getting a true 11mpg with current setup do a happy dance . These bricks are not gonna get 18mpg despite the constant claims we all see here.

02-09-2007, 11:40 PM	#17
bulky Bulky Join Date: Aug 2004 Location: Rhode Island Posts: 163	Re: improving fuel milege??? You could always do the "Poor Man's" Gear Vendor..... This is an old "DoodleBug" for sale up here locally. It has a 4 speed attached to a 3 speed. Attached Images __________________ 2016 Silverado 1930 Model A Hot Rod 1923 Ford A/SR Altered - Injected 409 1982 Honda CB900F Super Sport Dad's 1970 GMC 9' Stepside Dad's 1969 GMC Custom Camper

02-10-2007, 08:23 AM	#19
grinch4om dang its hot Join Date: Nov 2006 Location: frankfort kentucky Posts: 1,349	Re: improving fuel milege??? do the 700 tranny, I have one behind my big block witha 2500 stall(lock up) and it does 16-17 on highway at 65mph, of course thats no wind and good baro pressure yadda yadda....

02-10-2007, 12:07 PM	#20
N2TRUX Happy to be here Join Date: Mar 2000 Location: Cypress, TX Posts: 39,021	Re: improving fuel milege??? Screw mpg, just focus an ET and forget the rest... __________________ Follow me on Facebook and Instagram @N2trux.com Articles- "Jake" the 84 to 74 crewcab "Elwood" the77_Remix 85 GMC Sierra "Scarlett" "Refining Sierra"

02-10-2007, 01:13 PM	#22
boatpuller Registered User Join Date: Sep 2005 Location: Sun City West, Az Posts: 3,822	Re: improving fuel milege??? i agee,if you want mpg....get a datsun. Last edited by boatpuller; 02-10-2007 at 01:13 PM.



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