Hello all,

I have a 1979 Ford F150 Supercab with a longbed and I want to know what my estimated gas mileage will be after I insert a new motor into it. I plan on putting a 400 motor into this truck with an after market timing chain, intake, and carb. The truck also weighs close to 6,000lbs.

What do you think the estimated gas mileage will be after the new engine is put into the truck?

Thanks!

 

10. Maybe 12 if you drive really easy.

 

Even after changing the timing chain and advancing it from 8 to 4 or 2?

 

If you get 12mpg then it's time to have a party. I have owned two of the 79 super cabs and ran them for about 10 years , 9 t0 10 most of the time . I had another one , same size with the 460 and it got 9 to 12 , some times. I don't drive them hard , all highway ,freeway use and no hills hardly at all. Used in my construction co. for hauling tools most of the time. If you want fairly good MPGs get a small ranger , these big boxes were not built to run cheap.

 

Are you taking about going from 8 degrees BTDC base timing to 4 or 2 degrees? That's retarding the timing. I wouldn't expect the engine to run very well at all that way. And I agree with RedNeck's estimate. Were you expecting better? Now that's funny right there.

 

I drive like an 80 year old man and average 12mpg on back roads and in town