92 F-150 question???
I'm assuming you mean axle. It will fit, as long as you take the hardware you need. I think you need the u-bolts and bracket from the bigger truck to go with the bigger axle. Why not take the springs while you're at it.
The problem that you will run into (two, actually...) is that you will need to shorten your driveshaft by a little bit to accomodate the larger differential. You will also need to carry two spares, as the larger trucks use 8 bolt axles.






