I have a 1979 Ford F900 Fire engine with 29,000 miles on it. I took it out the other day and 40mph was my top speed. Is there anyone e on here familiar with these motors?

 

You’ll probably have better luck in the big truck forum. If I were to guess that sounds about right. Big truck + low gears usually means low top speed.

 

I understand big truck low gears, I just find it hard to believe that a fire engine in an emergency could only drive 40mph to a fire. Thank you for the big truck recommendation.

 

Something is out of whack. no on hi way truck in this era had a top speed that low. if it has a 2 speed rear axle did you shift it up ?

 

It doesn't have 2 speed rear axle.

 

Did the truck come from a city? I could see a crowded city being OK for a truck with a top speed of 40 MPH.

 

Came from Clemens North Carolina, speed governor has been removed so I am told

 

What transmission does it have ? what's the max RPM you can get out of the engine ?

 

5 speed manual but not sure on the size, 4000 rpm

 

Rare for a 5 speed not to have a 2 speed rear. very rare., I'm not even sure you could buy it that way.

Have you looked on the rear axle to see if there is a shift mechanism ? if it doesn't I'd jack it up and check your gear ratio.