I put a set Timbern suspension load dump stops on my truck, cheaper then airbags and your truck well keep its factory ride hight. Plus there is nothing to air up/down and your don't have to worry about a bag blowing out. They make them for small trucks to big rigs.
Oh I put them on a C8500 dump truck, and they are rated at 15000lbs each. Just took off factory bump stops and bolted the Timbern in to place.
You might want to look into these, they are not as expensive as airbags and work great. Pic is what some of them look like