They should have been able to find the numbers in their catalog, especially if they carry the National brand bearings. However, rather than dealing with a parts house that may not be able to get the right ones, I would suggest that you check out the specia;ty suppliers, like the American Classic link at the top of the page. They have the bearings that you need as well as the tapered roller upgrade. The prices are reasonable, and you will know they will be the correct part.
