what kind of mileage are you getting

I have been messing alot with my timing and Qjet, to optimize the engine and make it as effeicient as possible. During this I have done alot of road testing to see how muh mileage I can squeeze out of the car.
I have build and modified many Qjets over the years and want to say I know exactly how to tune this carb. The same goes for timing.

So my Qjet is modified and I have found the best jet/rod combination for it giving the highest mileage optainable with the best throttle response and power. ( the leanest setting possible with out hurting power )
Timing is bumped up to 17 initial with a 33 total. vacum advance is 15. all in by about 3000.
If one knows his SBC timing, he will know that these are close to perfect numbers for a mild 350.

The problem is I just cant get mileage above 20 mpg. This is based on consistent 50 mph driving.
The car is a 1979 Caprice with the LM1 170 hp 350. completely stock but with a muffler were the cat was and 2.5" pipe all the way to the rear bumper.

I had a ´79 Caprice with a stock 305 once, and that thing was able to hit 21-22 mpg average.
I am making sure I know exactly how many miles I drive. I dont just go by the odometer. its inaccurate.

I realize this is not a topic concerns too many poeple. I would like to point out that I am not obsessed with mileage because I cant afford driving my car. It is simply because I want the engine as effeicient as possible.

Please share your own results.
I have heard of poeple getting around 23-24 mpg in a carburatted B-body. I dont believe it... :-)

seriously, no one knows their mileage?

Marx3 wrote:seriously, no one knows their mileage?

The last time I checked my mileage while attempting to very conservatively sip gas I was right at 19-20 MPG. My car has dual exhaust, otherwise the 350 is completely stock. I'd say it could be possible... if most of the driving was only done down hill, otherwise I wouldn't count on it as a long term overall average for MPG's.

just my .02

wel sounds like you hit the same mileage I am.
I just cant pinch more miles out of it. No matter what I do to the timing and the jetting.
Richer, leaner, 19.5 mpg is the best I can do.

19mpg with my '84 wagon (canadian 305) mostly on highway

Thanks for sharing :-)

That's a question that holds some interest as I just had a bear of a time getting my 305 running properly due to

many old or bad parts. Everything on my 305 is new now except the bare long block with a 600cfm and rolling 205/60

front and 225/70 rear.(it was a bit worse with the 295/50 on the rear I just took off for the winter prob 1-2mpg.

I am getting 16-18mpg in the city I haven't done too much highway so I don't know what it is I'd guess 20mpg as my

rear end is 3.08 with the th350 i'm turning close to 2300rpm@65. I probably would do better on a rural road doing

45-50mph. When I get my th200-4r in I should see much better numbers.

My current Caprice does not run but is a 350 car. My first Caprice had a 305 and after it blew up, was replaced with a 355 and 350 turbo transmission. I never remember calculating the gas mileage because, back then gas was CHEAP! When I first got my license and that car, it was 97 cents/gallon. There wasn't too much worry about fuel mileage then. When I get this new Caprice built, I'll probably calculate the fuel mileage, but it won't be a big deal because it won't be a daily driver.

I can only dream of gas that's THAT cheap :-) The cheapest I can remember, here in Denmark, was about 4$/gallon.
That was 10 years ago. Gas is 5.8$/gallon on a good day, here now.

Anywas, like I said, I am not concerned about mileage because I cant afford to drive my car. I am interested in knowing what mileage others have seen, to get an idea of how well adjusted mine own car is.
I am about to put in a 3.08 rear end and maybe a 4L60 If I can get my hands on it.
That should lower the final drive ratio some, even compared to running 2.41's
Also, I just did some calculations and due to the lower 1st and 2nd gear ratio of the 4L60, the resulting final ratio is about the same for th350/3.08 and 4L60/2.41, but with the 4L60 I should hit 50 mph at about 1100 rpm.
maybe 24mpg is possible then :-)

I do remember filling up in NJ back in 94' and paid 80c a gal which was so cheap even back then I filled it to the brim

lol and the gas can! But gas isn't bad though here I just paid 2.56 for 89 octane. Still the days of riding in granpas 65

New Yorker Big Block and him paying 32c gal is hard to believe now.

I can only dream of gas being so cheap, it didn't matter what mileage your car got :-)
There are proably pros and cons to both our countries :-)
expensive gas, well, yes but the wage is high, 38% tax, well, yeah, but the hospital is free and you get paid to get an education. Many people here in DK would prefer a country that was more like the US is set up, though.

And people here in the US would prefer our country to be more like yours, and vice versa. Everyone wants what everyone else has, thats the way it goes! But gas is cheaper now than it has been in recent years, when i first started driving it was 4.89 a gallon for regular, this was in 2008, i had a car but couldnt drive it to school, had to take the bus, cuz i had no job, just a broke high schooler with dreams lol, that was my first car my 84 caprice 4 door, loved it while i had it.

Lol that's funny back in the summer of 08' I was chauffeuring my sister around in her 78' Lesabre with the Pontiac

301(Joy) and remember those gas prices oh so well. It's probably a good thing for her it was a 2 barrel !For the mpg

record I think that 301 2bbl averaged about 18-19mpg hwy.