The Stovebolt Site Forums The Shop Area General Truck Talk Gas Mileage

I've been getting 11 to 12 mpg in the city with my 235 and 1 barrel carb. Just wondering what others are getting in comparison with the same size engine.

Mark

I'm getting 15 but I have a 3.38 rear end

Just got back from a 1,000 mile trip in a '52, 3104 with the stock 216, 3sp, and 4.10 gear, the carb was a Carter W-1 however.
We averaged about 16.5 mpg running most of the way at between 50-55mph.
Denny Graham
Sandwich, IL

I can usually get the mileage up to 13 or so if I do more freeway driving but the stop and go of city driving takes its toll. I'm wondering if I should switch to a higher octane gas. I keep the engine tuned pretty well.

Speaking of fuel...

Are you guys using additives with each tank. I'm not on the road yet but I'm thinking about what an engine designed for leaded fuel might need.

Thanks

14 mpg in my mixed commute and 17 on the highway. GMC 270 with an SM420 and 3.08 gears.

19mpg in town.highway 22mpg.51 3100. 350cid,365hp.700r4 tranny,Ford 9" rear end 3.33 gears.

Mark, you should be getting better than that with the '57. You didn't mention what transmission or rear-end gear you have in it, but if it's completely stock and the engine isn't worn out, 16-18 is a realistic figure.

As for using high octane fuel helping with your milage, no, it isn't going to change that, just cost you more for fuel. The compression ratio of an engine is the determining factor as to what octane rated fuel to run. The higher octane fuel is meant for high compression, high performance engines, your 235 should run just fine on regular.

Needing to use the lead substitute additives as a valve lubricant is a myth. The TEL (tetraethyl lead) was added back around WWI as a cheap way to boost the ‘octane rating’ to prevent premature detonations. TEL made a lot of money for the investors in the Ethyl Corp. Octane contains 8 carbon atoms linked together, and it will spontaneously combust even at low compression ratios. An 87 octane rated fuel is 87% octane and 13% other blends like heptane or other fuels used to adjust the rating. This is more costly than simply adding TEL. Also Alcohol blends will also boosts the octane rating.
Denny Graham
Sandwich, IL

I have a 54/3100 with a 2.73 rear end and T-5 trans and 2 rochester's , dual exhaust 15" tires and around town i get 12-14 and on the road i can get as high as 23.5 and averaged 20 on the trip to KC and back, 1100 miles running 70 mph.

Stop worrying about your engine and think about what kind of gearing you have.I am running a built 350 tied to a 700R4 overdrive tranny.then into a stock 3:90 rearend. I get 20 MPG all day long,because of the OD tranny.And with that wicked low gear in the 700R4 it will blow the doors off of most cars that wanna drag race with me.Way too many people are looking for good performance and fuel economy,without looking at how they are geared.

The mileage is only important if you drive many miles.
I just enjoy the drive and forget the mpg.

Hey: Don't feel to bad, my 235 in my 2 ton must get about 5 MPG if I,m lucky. I have to buy gas allmost every time I take it out!

This past weekend I got 15 1/2 combo hwy/city. have a 261 .060 over with a howard m4f cam and a holley /weber 2bl carb from Tom Langdon, also a 3.90 rear end.

The factor determining fuel use is how many times a piston goes up and down in one mile. Every other time it takes in a mixture of one part fuel to fifteen parts air so the more times it goes up and down the more fuel it will use. The ONLY way to slow the piston cycles down is through gearing. That's the physics, but in the real world gearing can be too shallow which leads to an open throttle/low manifold vacuum condition that uses fuel, tire type and inflation, wheel alignment(front and rear), increased friction like brakes dragging and dry or tight/loose bearings, engine temp too low, carb not adjusted correctly, state of tune, free flowing exhaust but NOT large diameter pipes, and the most important factor IS THE DRIVER. Our shop truck goes through a tank every two days with one driver and every three days with the other.

I get 16 mpg in my 1 Ton, empty or loaded, my commute is mostly around 25-35 MPH. I have stock (5.14) gears in the back end, and big bias ply tires. I like the low gears in the back, as I can shift into 4th at 20 mph.

In my opinion, if you are driving in the city, the only way you are going to increase the mileage you get, is to drive with a light foot. At the same RPM, you burn more gas with your foot to the floor, than with it closer to idle.

I got 16 mpg with my 55 2nd with the 235 3 speed and original rear end.

Talking about Gas mileage.

Has anyone seen a higher or lower mileage after changing from a 216 to a 235 in their vehicle ?
By the way you are lucky with the gas prices in the States here it cost more as $ 8 per gallon.
Thank you

Jianis

56 3100, not stock 305/turbo 350 with stock rear end, i think 390 gears, 10mpg on hi way, 12mpg in town

A side note. waited until today to fill up and gas has gone 20 cents a gallon in two days.

When I installed the T-5 and modern rear end behind the 235 in my 37 the gas mileage got worse,those motors are not designed to spin so slow with the original carb so I have been tweeking the carb some and got it better but the 2.79 gears are too tall so I am going to install 3.50 gears and continue the tuning. I put in a smaller jet and lighter power valve spring but I think the power valve spring is not light enough.

i never much checked the MPG until i had it finished and i have a t-5 with 2.73 rearend and i have wondered if a higher ratio would help especially around town, let me know how it works out. ron

'53 6100-2spd rear-6.10/8.13-235-4 spd trans. 8-9 mpg, 0-60 never going to happen

Mom bought a bug when she wrecked her 67 Olds to get her by til it was fixed. I remember her saying every time we took off "0-60 sometime today" Of course after getting it to 60 it ran great.