I have a 1989 F250 extended cab long bed 460 Automatic 2 wheel Drive, there is about 3,000 miles on the motor and transmission, new paint & tires, its a very nice truck but I only get between 7 & 8 mpg, even the old motor did. I have read and talked with people who get 10 to 12 mpg. I hear things like rear end and overdrive will make a difference. does anyone have any experence on things to do to increase the mpg? thanks for any help

 

I have an 89 with extended cab, 4X4, 460, C6 tranny, 3.55 gears. Stock size tires etc. I get about 10mpg with the front hubs locked in but in 2 hi. I can get 12mpg or so steady 60-65mph. But in the winter in town driving, short trips warming it up etc it gets 7-8 mpg. I am running a k&N air filter, 3" cat back with Cherry bomb muffler. I have advanced the timing to 12* vs stock 10*. Unfortunately these 460's like to drink gasoline.

 

Thank you very much your responce is much appreaciated.

 

What transmission do you run? Their are things you can do to help within to free up some drag in tranny and upgrade on torque converters for your application. It can possibly free up 1 to 2 mpg with correct set up. Make sure your engine is tuned properly also.

 

What rear end ratio do you have. I run a 2.92 in my 460 and pull a holiday trailer with it. It has plenty of power and hauls that trailer well past 100mph while passing uphill. It also has a few other changes but the thing is that big power can pull big gears and not suffer much. Mine is a 79 460 F150 with a 725 Demon carb, headers and 2 1/2 inch exhaust with msd ignition and the timing gears from a 72 429 interceptor. I am going to put in a Comp cams 260H with lifters and a few other things to help it out in the mileage dept yet too. Last truck I did with this "junk" as some people say pulled off 18 and 19 MPG (canadian-imperial Gallons) per mile. Top speed wa 142 MPH at 4800 RPM. 3300 rpm is about 100 MPH with the truck by itself.

 

i'm not sure what transmission it is listed as a K, i'm not sure what rear end it has either

 

I have a C6 transmission. how can I tell what rear end I have?

 

There should be a tag on one of the bolts on the rear end with some numbers/letters on it. If you get tose numbers someone should be able to help you from there. Maybe search for em on site.

 

That 89 is injected isnt it? If it is, have you checked the O2 sensor? Like oldboy460 said, the early crank gear helps put timing back advanced (more) for the cam. I dont know how the 89 (FI's) are timed, but the earlier low compression 460 really loved lots of early timing, particularly for no-load cruising. Dont go a lot of initial, but mid-range mechanical and vacuum. You have to do some custom work on the distributor for the advance, but it does help. I guess you also have a dana 61 or 70 rearend, dont think they put the 60 in 250's---maybe wrong on that. That could be a biggie if the ratio is too low. No need to spin the 460 up unless you are hauling. The earlier crank gear will help get more lower end torque.

 

Thank you all.

 

Thank you all.