Hey guys.

There is a /6 fullsize truck for sale near me with a 4sp OD trany. What would one expect to get milage wise out of one of these?

I 318/727 truck gets about 10mpg

My full size 1985 d-150 with slant six and 727 trans gets between 9 and 13 mpg. This is a super six without the lean burn computer. 9 is all local and in short trips with a cold motor each trip (my morning commute is only 5 mins.) 13 is all highway at around 55 mph averaged over two full tanks.

I would guess you could do only a little better with the 4 speed. I've been practicing driving with a vacuum gauge and I hope I can retrain my foot for a little better results.

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1980 Aspen 225 super six

I am currently working on my 86 Dodge shorty an to get better mileage. Currently setup is a 225 running HEI, non lean burn BBD on a homemade intake, a 904 tranny, and 3.54 rear axle gears. I am currently getting slightly more than 10 MPG mixed city/highway driving, but I know that my homemade intake manifold has a moderate vacuum leak so I will be swapping to an Offy soon.

A vacuum guage is a definite plus. I even found one on Ebay called an Ecomony Meter that has what levels of vacuum give, poor, good, best economy.

Another thing to mess with is the timing curve. This can really make a difference in MPG.

The rear gears will make a big difference. I would hope the truck had 3.5s or something similar. This would let it get moving easier and he o/d would help MsPG on the highway.

Basically stock with mild cam, BBD, and 904 auto: 15 mpg

More warmed over (head work, 10:1 compression) cam, 4 bbl holley: 14.5-15 mpg.

Basically no matter how I drive it. Still has the 904 auto.

With an OD manual, and the engine in good tune, I would think 18 mpg (highway) would be reasonable with a 4 speed OD manual. $0.02

-S/6

i'm getting right at 20mpg on hwy trips with slightly less around town....18+mpg with mixed hwy/city driving.

3.21s and 833OD


sb

87 short bed 225 with recurved electronic ignition, super 6, 2 1/4 exhaust, 3.90 gears, lockup tranny, 13 MPG.

Thanks for the input...

mopar_nocar, what year is your truck?

The one im checking out is a '80 fullsize.

mine is an 82.

i drive conservatively in the truck....no jack rabbit starts, accelerate at a moderate pace...i imagine if i drove it to keep up with stop light to stop light traffic, i'd get MUCH poorer economy. (in fact, i was noticing a Geo Metro passing me from a stop light today lol)

once on the hwy i keep it in OD as much as possible and only downshift to third if i NEED to. its working for me. i haven't tried towing any distance yet with it, but i need to put different gears in it if i do tow....

sb

I used to have a '77 Dodge van with a slant and 3.55's and an O.D. 4speed I swapped in. I was able to get 21-22 mpg on the highway with that setup. I think high teens should be well within reach with your truck. I have an '83 W150 with a slant and the big heavy-duty 4speed (no O.D.) 3.55's and when the thing was tuned up decent I could get around 18 on the highway with that.