This is a bus conversion site. Some buses are simply medium sized duty trucks with bus cabins on them. However something that old, 1934, people on here aren't likely to know the answer to that.
What you can do is since it's an international harvestor, is call Navistar and ask for a part number, then you can search on the net for one. They won't have such a part in stock, but someone on the net will have an after market. The part number will lead you there. Even if there isn't a number on the item (as it's old it likely doesn't) Navistar should have an internal number that others would use for such a part for searching purposes. Call any International/Navistar stealership, and ask for parts department, and tell them what you are looking for is a part number for X.