Hello,

This is my first post on these excellent forums,and I'd like to know the following-

What sort of gas mileage should I be getting from my 55 Fairlane ,(it has a '57 Merc 312 with a stock 4 barrel Holley,and a Fordamatic trans)?

It seems pretty thirsty!



Thanks in advance,



Chris.

Remember they were built in the days of cheap gas so they are not going to be anywhere close to modern cars,I would say 14 to 18 on the highway should be what they got.

Butchering up everything I can get my hands on in Dayton Ohio

Thanks Jeff.



I forgot to mention I'm in the UK where fuel is now about $7.50 for a US gallon.



I LOVE driving my '55,it's just very expensive to do so over here now.



Chris.

That appears to be about right considering the exchange rate.........however the price also includes about a 170% tax on the wholesale price. I had no idea the taxes on motor fuel was so high in the UK!  http://www.abd.org.uk/fuel_tax.htm






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1955 F-600/272/E4OD// Disclaimer: No animals were injured while test driving my F-600 except the ones I ran over intentionally!

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This post was created using OpenSuSE Linux x64 and Firefox

Think that's why in the UK they would drive little Vauxhaul's and Morris Minors! Gas was high even in the 50's and 60's compared to the U.S.

With a little tweeking you might be able to get a little more mileage,add a electronic ignition and tune the carb some and see what you get.  To be able to get different size jets for the carb you might have to go with a modern carb.

Butchering up everything I can get my hands on in Dayton Ohio

Tweaking will do some......taller gears will make a large difference too.



You will want the engine turning around 2000 or less on the highway to get good mileage....

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1955 F-600/272/E4OD// Disclaimer: No animals were injured while test driving my F-600 except the ones I ran over intentionally!

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This post was created using OpenSuSE Linux x64 and Firefox

Does the engine load up at idle, or is it very difficult to start when hot and has been sitting a while?  If so, the power valve in the carb may be leaking.  That will increase fuel consumption drastically.

John - "The Hoosier Hurricane"

You didn’t say what gearing but assuming 3.23’s or thereabouts and depending upon the wear in the engine then minimum expectations would be 13-15mpg for town driving and 15-18mpg on the highway.  This is for a stock ’57 312 combination that’s in a reasonably good state of tune with a properly working mechanical and vacuum advance within the distributor.  And that’s with todays U.S. gasoline.  If you can find some gasoline that does not have alcohol in it, then fuel mileage will jump up another notch accordingly.

 

John brings up a good point on the ’57 and up Holley power valves.  Age tends to stiffen the diaphram in those and as a result, more vacuum is required to close them.  There’s a point that they don’t close at all and the engines are running with the extra fuel being supplied all the time.

Lorena, Texas (South of Waco)

I would also raise the timing from the ford specs of 6 degrees btc to 10 or 12 degrees btc if you have'nt done it yet with the vacuum advance disconnected. When done reconnect the vacuum advance and see if this helps gas miliage and power.

-Gary Burnette-