Many stock leaf spring axles are mounted over the leaf springs from the factory. This is generally done to avoid issues with axle wrap (basically the axle twists the leafs into an S-shape). A common and cheap way to lift a leaf spring vehicle is to simply install pads on the top of the axle tube and mount the axle underneath the leaf springs. This lifts the vehicle about 5 inches with very little change in suspension geometry and very little cost, just some welding and rebolting. Those are both leaf spring pads on top and under the axle. The previous owner simply left the pads on the bottom so it could be returned to stock with no welding.
Most users here will recommend 1541H instead of chromoly shafts for the Dana 35, due to the inner bearing race being the shaft itself. If replacing the carrier and the shafts at the same time, it may be worth switching to 30 spline axles, which aren't much more expensive, but significantly stronger.
That is what I meant, 1541h 30 spline shafts are frequently misrepresented by calling them chromolly. But they do come in Chromolly as 27 spline. My bad.
