What are the quantities of the fuel tanks on an 87 F250 with the 6.9L? I just took a trip and got 266.1 miles out of the rear tank. Sound about right?

Also, I took that trip, essentially unladen, doing 60mph turning 2700rpm on the tach in 4th gear (She's a 4 speed manual tranny). Any ideas for what the gearing is for the 4th gear or the rear end?

Thanks guys!

 

I think the tanks are 17 front and 19 rear.

Assuming a tire size of around 31" I'd guess 4.10 gears. High gear in the four speed is 1:1

 

12-14 mpg sounds about right to me for your set-up without an overdrive.

In comparison I got the ZF5 Overdrive tranny with the 3:55 rear end and do +20 mpg at 60mph, no load with the engine turning about 1900 rpm with 3 psig of turbo boost.

The overdrive trannies have made a significant improvement to fuel economy on these trucks.


Seb....