Ingersoll discs is what you want. If you can find a local dealer or a distributor close by. http://www.ingersolltillage.com/
The Ingersoll discs are what CaseIH uses on their equipment. Only difference is that the CaseIH ones have "Earth Metal" and a CNH logo stamped in them. I bought some through Agris2000 here locally.
CaseIH vs Shoup, planter rebuild
