Are you talking about the spring perches that weld to the axle tubes? If so, I haven't ever found any at the tractor supply stores that are as wide as the automotive leaf springs, just the narrow little trailer springs. If you are needing the torque plate that the U-bolts go through, all you need are the plates that are as wide as your springs and U-bolts and are made with a heavy enough guage steel. Hope this is what you are needing,
Scott