gas mileage?
Instructor
Joined: Jan 2013
Posts: 115
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From: Los Angeles
The transmission and overall condition of the car will make a big difference. I drove my 1979 L48 with a Camaro T5 from Utah to SoCal and averaged 19.5 mpg for the trip. Stock tire size, 3.55 rear gears. The carb and ignition were properly adjusted, alignment was good, brakes were not dragging, etc. I don't think I could get much better MPG than that without going to EFI, and even then maybe only 5-10% better.
I did the same trip in C30 pickup with a TBI 350 and got an average of 6 mpg. The rear brakes were dragging just a tiny bit and it definitely needs a tune up, but that truck should get at least 12mpg if it was working properly...
If your car is stock and reasonably well maintained I would expect at least 12 mpg with an auto.
Or 15+ with a manual, and a tiny bit better with an overdrive trans.
I did the same trip in C30 pickup with a TBI 350 and got an average of 6 mpg. The rear brakes were dragging just a tiny bit and it definitely needs a tune up, but that truck should get at least 12mpg if it was working properly...
If your car is stock and reasonably well maintained I would expect at least 12 mpg with an auto.
Or 15+ with a manual, and a tiny bit better with an overdrive trans.
Last edited by kkEdlund; Mar 6, 2022 at 05:34 PM.
Team Owner
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From: Southern Cal Ca
St. Jude Donor '22
depends on gear ration of rearend.
and the cubic inch of motor.
add in the amount of time of city driving verses hiway non stop.
generally small block 12-16 with 16 being hiway.
and the cubic inch of motor.
add in the amount of time of city driving verses hiway non stop.
generally small block 12-16 with 16 being hiway.
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From: New Or-leens Loo-z-anna
You might be surprised how much slippage occurs in a A/T even if it feels O.K.
A rebuild kit/clutches seals orings could really help if the trans has never been rebuilt.
The basic kit $200 to $300 (no sun gear-etc replacement if they arent sloppy) would pay for itself with gas prices climbing.
You could rebuild it yourself in one weekend/no experience needed...if you buy a rebuild softcover book w/stepbystep directions.
A rebuild kit/clutches seals orings could really help if the trans has never been rebuilt.
The basic kit $200 to $300 (no sun gear-etc replacement if they arent sloppy) would pay for itself with gas prices climbing.
You could rebuild it yourself in one weekend/no experience needed...if you buy a rebuild softcover book w/stepbystep directions.
Le Mans Master
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From: Hermosa
Race Director
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I'm thinking the 12 - 16 MPG answer was pretty much on line. I've had my 77 for a lot of years, and many of those it was bone stock. And that sounds about right.
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And Automatics usually get worse.
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Dr. Detroit
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From: New Braunfels Texas
A free breathing 76' Vette will get 17mpg as long as it has the 3.08 gear.......but it has to be performance tuned.....
The first thing you do is remove the miserable exhaust starting from the heads right on back.....
Jebby
The first thing you do is remove the miserable exhaust starting from the heads right on back.....
Jebby
Le Mans Master
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From: Omaha NE
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The cat has the same flow rate as a box of frozen peas and the mufflers aren't much better.I have Corvette Central's 2 1/2" dual system with Magnaflows on mine and it really made a difference.
I did get 18 mpg once back in the day coming back from Colorado. And that was bone stock.
Maybe I had a tailwind...
...
Race Director
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From: FL
The cat has the same flow rate as a box of frozen peas and the mufflers aren't much better.I have Corvette Central's 2 1/2" dual system with Magnaflows on mine and it really made a difference.
I did get 18 mpg once back in the day coming back from Colorado. And that was bone stock.
Maybe I had a tailwind...
...
Team Owner
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From: Southern Cal Ca
St. Jude Donor '22
Melting Slicks
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Damn, I can get more MPGs out of a healthy Pontiac 455 lol
I'm surprised these cars struggled to break into the higher teens. Aerodynamic, somewhat lightweight, and a Q-Jet with tiny primaries. Oh well, nobody drives them for fuel efficiency anyway
I'm surprised these cars struggled to break into the higher teens. Aerodynamic, somewhat lightweight, and a Q-Jet with tiny primaries. Oh well, nobody drives them for fuel efficiency anyway
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From: Compound in the Grove, Ga.
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St. Jude Donor '16
My good old 82 CF gets the best of any C3 I have owned with 20-22 on the highway.
