i have a 1991 f150 2wd and when ever i go offroad with it (not mudding) if i hit the smallest bump it feels like the whole truck is gonna fall apart is it suppost to be this rough?

 

I'd have to say no it's not supposed to be that rough but then it depends how fast you are travelling and what exactly you mean by "the whole truck is gonna fall apart". These trucks aren't exactly the most elegent off roaders and don't handle washboard for example as smoothly as the newer trucks, but overall they will perform adequately at reasonable speeds.
If you are getting loud metal on metal bangs from the front end one or both bump stops are missing, or the shocks could be shot or the wrong model for the truck even. If that isn't the problem maybe decribe what you are experiencing in more detail so we have a better idea where the problem is.

 

Like if im driving and I hit bumps .....the bed moves alot...and the whole thing just feels like theres f350 suspension on it

 

perhaps the body mounts need replaced. may also need new shocks as well. What tires are you running and at what pressure.

 

The body mounts have some cracking on them......my tires are 31nittos and I dont keep them at full pressure

 

There is a lot of frame flex with these trucks so you can expect the box to wiggle around quite a bit in relation to the cab. With older trucks you never know what a previous owner may have done, maybe the truck does have heavier springs in it or air shocks.. who knows. Does it sit high? It shouldn't being a 2wd, those 31's should be almost touching the front fenders when parked on level ground.

 

ya the front tires are almost hitting the fenders