Slant mpg

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J

JoseyWales

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What should I expect from a 225 as far as mpg goes? I have a 75 Duster that I am going to start using as work transportation. I just gave it a tune up and it is running great. It has dual exhaust with a single bbl carb. What do you think it will do? I am hoping it gets better mileage than my Jeep Rubicon, It gets 13 on a great day. I guess you cant expect much out of 4.11s and 33 inch tires with a 4.0L though.
 
I am going to let the /6 guys handle this one but I would have to believe that lower-mid 20's would be fairly easy to achieve.
 
Drive it nice and you should get mid to high 20's depending on how far and how fast you drive. I have a Mopar friend that gets 27hwy with a 46 Plymouth
coupe with a slant and a 833 od. trans. It's a tubbed 8 3/4 with 3??? gears. I
get 20mpg with my 66 Dart with the HP273.
You should do good! Mike
 
My dead stock 65 Dart gets 20-22 in town, and 25 or so on the highway. Well thats on a 2-lane highway. Our freeway speed limit is 75 and traffic moves about 80. Running it that hard, I drop back to 20 or so.
 
Driving hard (70-75mph) I am getting about 19.5mpg. That is with 3.23s, cam and headers. I am in CO so keep the altitude in mind.
 
I have tried to figure this out also. I have put a full tank in a few times, i drive 10 miles a day, leave it parked on the weekend. My gauge doesnt work so at 100 miles i fill it up. Both times i have put in 6 gallons.

My commute is fairly flat also
 
I have never gotten any better that 18 with a 225 /6 that is why I quite running them and run 318's I get about 17 with them on the same commute. I don't know why and I hear from lots of 225 /6 guys getting much better but I haven't been able too.


Chuck
 
I will start driving it to work next week, I will post my results at the end of the week. It is a 32 mile drive one way. My speedo is not 100% so I will use my handheld gps to figure it. I am hoping to get around 20. How much does the stock tank hold?
 
i think the tank on the scamp is 15 gallons maybe, my engine has been rebuilt and i rebuilt the carb also.
 
I was getting around low 20's then I switched to a 2 bbl manifold and a motocraft 2100 carb and got just below 30 MPG. If you are getting bad MPG you might need a carb rebuild, very common week point on the slant. 1 bbl is way to small so it bogs down your power and MPG.
 
Ya, i definitely get somewhere between 20-24 miles to the gallon.

Has anyone else seen MPG increase when they switched to a 2 barrel carb and manifold?
 
i got about 13 mpg in my slant six 3 speed on the tree wagon, pretty bad, it wasnt probably in the best mechanical shape...but the engine sure looked awesome;)
 
you can always add a efi system which should improve the mileage
 
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