leveling kit
 

I have 2004 F150 FX4 was wondering what size leveling kit I should buy to get truck level 3" or 2.5" kit

Pull out the ole measuring tape, it varies truck to truck. If you're in between sizes, I'd round to the lower size.

not sure how to measure i measured the diff from rear and front bumper it was bout 4" or more

Most people recommend using the top of the fender arch as a reference point, measure from the center of the hub to the top of the fender.

Thinks looks like 2.5" will work

2.5 should be fine, thats what I had on mine. But I did not like it at all!!! It brought the front wheels closer together. Made the truck look like it needed wide rims really bad!!! I had just purchased new tires & did not want rims. I ended up lowering the rear 2" with shackles and lifting the front about 3/4" to level the truck. Looks like thats the way it should have been from the factory, not extreme at all. Plus I would always get flashed when I was running my fog lights, not anymore.