Do yourself a favor and call GCH or if you have the machine / head measure the ID and call an industrial bearing house.. If you have a cone it should be easy for them to figure it out. In a head that is probably over 50 years old your gong to have a hard time getting much help. John is probably the most experience guy on here that would know and he sent you what he is offering. GCH also does trades, you send the old one and they will send one back that is reconditioned or rebuilt. Give them a call, will save you some time and it can't hurt.