I can't hit 140kmh.... help
 

I got a 1996 F-150 MAF 351 e4od with 3.55 LS in the rear. I have issues going faster than 140 km a hour,
what gives?
also im on 35x12.5r15 rubber. so is it gearing?
I plan on running 33x12.5r15 rubber with 4.10 gears. what cam would work good with a truck that will
see:
Offroad use (light trail running no rock climbing or any of that crap.
Drag strip usage (actually my truck runs 17.9 in the 1/4)
retain daily drivability.
end goal is to be 13.99 on fuel.
so I think on 33's Heads Cam Intake I should be almost there right. might need some nitrous.
as you can tell this truck is a toy. nothing more.

Have you got rid of the speed governor? I believe the max speed with it is 96mph so with the 35 tires and you running stock gearing you're probably hitting the governor. Just my .02

With 35" tires your speedo is WAY off, unless you recalibrated it you were actually going 165kph. And with 3.55 gears the motor doesn't have enough grunt to push the brick any faster, you need 4.10 or 4.56 gears.