gas mileage

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Jan 20, 2014 | 11:50 PM

Blame

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Joined: Jul 2010

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From: Jacksonville Fl

gas mileage

Had some reject make a statement about carbs making 14 mpg.

I know for a fact my 81 does 18 mpg avg. And ill improve on that in the coming months.

So how good is your gas mileage with a carburator?

(I AM NOT WORRIED ABOUT MY GAS MILEAGE, IM ONLY COMPAIRING MY MILEAGE TO OTHERS BECAUSE IM CURIOUS)

Last edited by Blame; Jan 25, 2014 at 03:31 PM.

Jan 21, 2014 | 12:01 AM

harris1507

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Posts: 517

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From: Orlando FL

I have a 502 and a Holley 850 and I get about 6-9 mpg. (maybe) If I drive easy, but it is hard when you have a car with this kind of power.

Jan 21, 2014 | 12:35 AM

John 65

Le Mans Master

Joined: Dec 2003

Posts: 5,381

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From: N J

454 with a Holley 750 DP. 10 MPG, but I cant complain, its fun to drive.

Jan 21, 2014 | 12:44 AM

CanadaGrant

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Joined: Apr 2006

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From: BC

My bone stock 69 427 4 spd gets about 9mpg. My wifes 78 L82 auto might get 16 on the highway on a good day, downhill....

Jan 21, 2014 | 12:50 AM

ddawson

Le Mans Master

Joined: Mar 2001

Posts: 5,738

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From: Lincoln, CA

Who cares. My 2004 GTO after mod was only getting 10 in town and 20 highway.

My 84 Mustang with a Holley got better.

Jan 21, 2014 | 02:07 AM

7T1vette

Team Owner

Joined: Jan 2006

Posts: 37,637

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From: Crossville TN

Fuel mileage is more related to the size of engine, the rear axle ratio, and whether it has an overdrive transmission and lockup on the tranny than anything else. Any carb in decent condition can be tuned to provide nearly the same mileage as if the car were computer controlled EFI. But, most carbs aren't tuned that well.

A SB C3 with O/D and 3.55 or lower rear gear should be able to get around 20 mpg at highway speeds.

Jan 21, 2014 | 05:58 AM

terrys6t8roadster

Melting Slicks

Joined: May 2012

Posts: 2,192

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From: Allenton Wisconsin

my 68 roadster has been known to get around 5mpg on the track, and if I try real hard I've gotten 16 on the highway. it's a 350 411rwhp overdriven with 373screws. Been waiting for someone to post about mileage. onto the 69 coupe, L46 auto and 3.08's. option loaded. [this type of car must be rare cause you never see 69 base coupes for sale on the forum]. took the replacement rodchester off and installed a spreadbore, now getting 21mpg on the hyway and 18 normal mix driving. planning more mods [electric fan, overdrive trans]. hoping to see around maybe 27mpg. how are other CF members doing and what mods are you doing?

Jan 21, 2014 | 06:03 AM

Blame

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Joined: Jul 2010

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From: Jacksonville Fl

LoL so low of mileage.

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Jan 21, 2014 | 06:30 AM

oldschoolvette

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From: Orlando FL

don't care fun is the real payoff in this matter

its about smiles/gallon and that number is quit large

Jan 21, 2014 | 07:02 AM

#10

Blame

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From: Jacksonville Fl

I care because I like improving on my vette performance and gas mileage.

Jan 21, 2014 | 07:58 AM

#11

harris1507

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From: Orlando FL

Quote:

Originally Posted by oldschoolvette

don't care fun is the real payoff in this matter

its about smiles/gallon and that number is quit large

In that case I get 100 smiles per mile

Jan 21, 2014 | 08:06 AM

#12

Mick71

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Joined: Nov 2010

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From: Bowtie, Pennsyltucky

St. Jude Donor '13-'14-'15,'21

I check mine all the time. My car is a stock 350/270, 4speed with 3.36 gears and I get between 12 and 18 mpg.

Jan 21, 2014 | 08:49 AM

#13

Revi

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Joined: Oct 2005

Posts: 1,615

Likes: 150

From: Forth Worth TX

Quote:

Originally Posted by Blame

I care because I like improving on my vette performance and gas mileage.

You're getting more performance and more gas mileage? That's interesting. Let us know when you get 500hp/500mpg.

Jan 21, 2014 | 08:56 AM

#14

doorgunner

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Joined: Sep 2013

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From: New Or-leens Loo-z-anna

Quote:

Originally Posted by CanadaGrant

My bone stock 69 427 4 spd gets about 9mpg. My wifes 78 L82 auto might get 16 on the highway on a good day, downhill....

Which proves that Corvettes were built for speed (and "gas stations")

Quote:

Originally Posted by oldschoolvette

don't care fun is the real payoff in this matter........its about smiles/gallon and that number is quit large

Which proves that Corvettes were built for F U N !

Quote:

Originally Posted by Blame

I care because I like improving on my vette performance and gas mileage.

Which proves that anything can be improved...even mpg in a Corvette.

I started with a 1934 pickup (same weight as Corvette) 350ciSBC(stock)15mpg w/any type transmission 3.43 diff. gears 90*F

added Holley 600CFM carb (out of box) 15mpg engine-vacuum 13 "lbs."@60mph@3000rpm

rejetted Holley (2 sizes smaller on all jets) re-timed engine 16mpg vacuum 14lbs.@60mph@3000rpm

added CAI 18mpg vacuum 15lbs@60mph

removed P/S and steel fan/added electric fans 20mpg vacuum 16lbs.@60mph@3000rpm

added 700R4 A/T 22mpg vacuum 15lbs.@60mph@2400rpm

removed 3.43 diff. gears/added 2.92 gears (bad mistake--should have added 3.08 or 3.18 gears) still 22mpg vacuum 12lbs.@2100rpm@60mph***

***Basically I reduced engine rpm about 20%(a good thing)...BUT...I also decreased vacuum about 25%(a very BAD thing)...If I would have been able to maintain 15lbs. vacuum--the mpg would have increase 2 or 3 mpg. (I will install 3.08 gears at the next opportunity)

I will keep a record in my project thread of my Corvette engine readings as I make changes (for those who want better mpg for long trips (and still want to spin the tires for fun...LOL)

You guys with the beast-engines...just keep having fun!

Last edited by doorgunner; Jan 21, 2014 at 09:01 AM.

Jan 21, 2014 | 09:28 AM

#15

Roco71

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Joined: Jul 2009

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From: Vero Beach FL

My 1971 350 gets about 14 MPG -15 MPG

Jan 21, 2014 | 09:37 AM

#16

bashcraft

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Joined: Jan 2006

Posts: 6,506

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From: Butler Pa

Quote:

Originally Posted by harris1507

I have a 502 and a Holley 850 and I get about 6-9 mpg. (maybe) If I drive easy, but it is hard when you have a car with this kind of power.

6-9? My 502 with the Holley 850, 3.55 gears and M20 got 13 mpg. I now have 3.08 gears and it still gets 13 mpg.

Jan 21, 2014 | 09:44 AM

#17

Blame

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From: Jacksonville Fl

Starting to love my small block even more

Jan 21, 2014 | 09:56 AM

#18

diehrd

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Joined: Jan 2009

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From: New York

430 hp / 3.92 gears .700R4 .. 15 to 16 mixed driving , I do have to point out in my City you get town to town by expressway so I am on the highway a lot.