Most of the classic truck part suppliers, along with the chassis suppliers sell stock height replacement coil springs. Before buying any of them, be sure to ask the wire diameter of their "stock" springs and compare this to your originals. Most are much heavier than stock and won't bounce at all unless the bed is fully loaded. Interestingly, most of the lowering springs are much smaller diameter than stock and greatly reduce the load capacity. You might be happier installing a set of used originals if you just want to keep it stock.
