Considerations about gas mileage

[WorkinLonghorn]

I get around 12 MPG with a 350(mild RV cam,lowered compression,otherwise stock) and 4spd. Sometimes I put in $120 in a week. I was thinking these old trucks are really gas hogs. Then I did some looking around and noticed that a new Dodge Ram got 11 with the 5.7 and 12 with the 4.7 when driven around by Consumer Reports.The others got 13 or 14,none higher.And these are "1/2 ton" trucks. Mine is a 3/4 and a heavy one at that,being a longhorn on a 1 ton frame. It weighs 5200 lbs on the scales. I went on another board where the guys with the GM 3/4 tons ( 6.0 Ltr ) were getting around 12 MPG ! Sure they have tons more power available to them, but for all the fancy multi-thousand dollar computer systems,not to mention initial prices of 30-40 grand after all is included,I am looking at my old work truck in a new light.
It's built like a tank as you all know,and it is so simple and easy to repair,I really don't think I am going to miss the "heated leather seats",at least not around L.A. anyway.-Brian

[JimKshortstep4x4]

Well said about your truck! They are great trucks and outside of gas mileage, they don't cost much to maintain.

We get 16 mpg on the highway with a 1/2 ton truck but my short step 4x4 just barely got 12 mpg on its last trip.

There are some things that can be worked on to make some improvements and there is a good article on mileage improvement in the August 07 issue of Carcraft that I believe is worth reading. I am going through my shortstep to try to get the mileage up. Even a 1 mpg improvement would help!

Jim

[ChevLoRay]

Not bad....mine gets about 9MPG just sitting still. I got a locking cap and drive it two or three times a month...gotta put gas in it every time I drive it.

[70 shorty]

I think what you have to look at also is not too many people can go out and lay out 40000 out of their pocket for a new 3/4 ton truck. I would think the vast majority of people that own trucks like our old ones own them outright. You can buy a lot of gas for that $600 a month or whatever the payment would be on that new truck.

[eedgell]

Yep, and the $600 a month, or what ever is for payment only. You still have to put gas in it. If you are real worried about MPG, then think about tall gears like 3:07's. That will help.

['68 longbed]

anybody ever try 3:55's in an otherwise stock truck. i used to run that in a belair and got right around 20 mpg

[Luvlegs]

and don't forget insurance! My 3/4 Ram (2500)- turbo Diesel averages 16 - mostly highway everday - take the 600 payment, add ~100 insurance, AND ~100/wkfor fuel - thats $1100+ per month! The wife can't figure out why I want to drive my I-6, 72, WITHOUT AIR, daily... I like it!

[GREASEMONKEY72]

my truck is my only vehicle and i get about 8-10mpg im not sure which but i have the stock 350/th350 and 3.07 gears with 30in tall tires, no ac

[HeavyD]

As far as gas mileage goes, trucks are a joke. If you can afford to spend the $$ then great, if not buy a beater for grocery getting. It won't hurt anything but your ego and you will have more cash to spend on the truck to make it even better.

[krue]

I drive a toy car for gas mileage, I drive my truck for work/fun.

[ETsC10]

Originally Posted by HeavyD

As far as gas mileage goes, trucks are a joke. If you can afford to spend the $$ then great, if not buy a beater for grocery getting. It won't hurt anything but your ego and you will have more cash to spend on the truck to make it even better.

Well, my ego (and, just the fun of it) keeps me in my truck...got the 26MPG 1980 Escort sittin' at home. I have no other hobbies so I consider my Chevy truck addiction fairly economical.

[randomhero472]

Im really suprised, my 06' f250 gets 15mpg... i thought it was a total gas hog! Im all about getting a scooter or little turd car to save me some $$

[wibilly]

i got a corvette for gas miliage it's not much better than my truck but 5 mpg adds up

[GREASEMONKEY72]

Originally Posted by wibilly

i got a corvette for gas miliage it's not much better than my truck but 5 mpg adds up

now THATS a mpg car to be proud of

[stsalvage]

What makes a 1/2 ton diffrent from a 3/4 ton a 1 ton from 2 ton Now 3ton we almost all Know is a Flat bed a bob tail or a box truck with a 15--22 inch box or steak bed.

But getting back to the 1/2 ton to the 1 ton frames what is the diffrence.
the 1968----72 Longhorn has a 133 wheel base and the 12 foot flat beds on the 3/4 to 1 ton has the 135 wheel bases but from other then that.What makes a 1/2 to diffrent from a 1 ton Frame



NOTHING the 1/2 frame is the same as the 1 ton frame when its in a 127 inches wheel base. So that dose not effect Gas milage.

I feel the chassic is what makes the diffrence on what the truck will be the front A arms and Rear End all the sheet metal is the same on the 1/2 ton to the 2 ton trucksand so on

[lowrollin70gmc]

Ummm.... other than the last post, some good revelations here. I don't even want to know my truck's mileage, although it wouldn't be so bad if I wasn't always driving it like a hot rod.

[jgrh64]

I haven't checked my mpg yet but it's at least double what my 64 gmc 305V6 4 speed was getting based on how fast the gauge moves based on a 20 mi freeway trip. It has allot to do with the tune of the engine, gearing , driving habits what brand of carburator. My friend had a '03 silverado 5.3 1/2 ton 4x4 10 mpg a $500 month payment and the last time a $600 repair bill for rough running -he sold it off and got an older less costly to repair truck without the monthly payment.

[Hook'em]

My 2004 Z71 Burb gets around 13 mpg. I haven't figured out the truck, but probably not much worse.

['68 longbed]

I'm thinking a taller tire might be a half decent short term attempt to help mileage and for the tractor gears on the highway. anybody have any luck with changing to taller tires?

[Ackattack]

I've gotten 16mpg in my 72 and that was "mostly" highway driving, so I might be able to eack out 17 or 18 just strickly highway driving.

I drive my corvette to work...usually about 23mpg mixed driving. I've gotten as good as 31 out on the highway.

[glock35ipsc]

I never had the 68 running long enough to figure it out

My 03 Chevy 1500, 5.3L/4L60E was getting 18-19 on the highway. I could squeeze 20-21 on a long, steady speed road trip.

Since I installed the W4M Performance PCM in my 02 GMC 1500HD 6.0L, I went from 13.0 to about 15.5 on the highway. Towing power is through the roof!

[eedgell]

STOP, AND THINK! For a minute about what you all already know!!! With all of this epa, and enviromental B.S over the course of almost 50 years. They are saving the planet, better gas mileage standards. Blended fuels. With all of this junk that just ends up costing us money, because we are the consumers of all of this regulation. How far have we come in fifty years? Our old trucks run with the newest of them, mpg, with all of this regulation to make them more fuel efficient, and more enviromentaly "friendly". They havent done jack in 50 years, but cost you and me alot of money. Old technology works just as good as new. 50 years worth. What good to the enviroment or your pocket book has the computer age been? According to the 50 years of hype, by now we should be driving our cars for free.

[Billy Ol' Blue]

My 72 longbed is a daily driver it get 16 mpg or 15.5 gallon tank a week 350 5.7 - 3 speed auto 4x4 600 cfm holley with vacum sec.

[Robert1970C20rstbukt]

I've been getting about 15MPG with the truck(no BS), that was city and highway driving and I fill it up once every two weeks. I never drive faster than 50-55 on the highway. The low mileage rebuilt 307 swap and HEI ignition upgrade helped a lot. I wanted to keep the 4bbl Quadrajet so we swapped manifolds and carbs from the blown 350 on to the 307. The transmission(1967 TH400) is stock and the rear axle has 4.10's with 33x12.50 tires. Not bad for a 5100lb truck! I don't even wanna know what my Suburban would get..................

[mnunn454]

To improve mileage may I suggest any/all of the following:

- Dual Exhaust with low restriction mufflers. (Plus Long tube headers if that's attractive to you.)
- You need a final drive ratio in the 2.5 to 2.8 to one range with normal 28" tall tires. If your tires are 10% taller than that, then maybe 2.8 to 3.0 to one would be about right. Highway engine RPM should be in the 2000 to 2200 range. Several ways to achieve this of course, Bolt on Overdrive, Change the ring and pinion, change to an overdrive tranny. R&P swap is the least expensive, but may hurt your 1st gear/takeoff performance.
- Measure the air/fuel ratio at normal cruising speeds. It should average in the 14.5 to 14.6:1 range. If it's not (it's probably in the 13.0:1 range), lean the idle and air-bleed circuits (not the main jets) of the carb until you get 14.6:1.
- If you don't have HEI ignition, get one. They're great.

- Make sure the timing is set as far advanced as you can run it, given the grade of gasoline you buy. Back it off one (1) degree at a time until it stops pinging. You may be able to have the distributor "recurved" to better fit your application, and eliminating a lot of the pinging.

- Add an MSD box (Multiple Spark Discharge) if resources allow. It sparks multiple times per cylinder stroke at anything under 3000 RPMs (which is where you'll be once you get that 2.7:1 final drive ratio.

- Pull the mechanical cooling fan and install dual electric puller fans with a shroud. It'll save about 12 horsepower which translates to about 5% of your engine's output at highway speeds.

Do "all the above" and you could get 16-17 MPG which translates to about a 30%-40% boost in mileage and an equal reduction in your gas bill.

JMO. Best wishes.