Old craftsman lathe

I have a craftsman lathe circa 1949 that need new bushings. It is a 103 series. This uses 2 1" od x 3/4 id x 1" long bushings and the 3/4" shaft rides in these. I'm wondering how hard it would be to replace them. I think it is probably an interference fit so I would need to heat the cast iron headstock housing to tap them out.
While the shaft is out I would like to have it threaded the same as my later 113 series lathe so the attachments (faceplates, 4 jaw chuck) would interchange.
How best to go about this; or should I just I just scrap the 78 pounds of cast iron?

I have two old Craftsman lathes and I replaced the bearings on one. It had the bronze sleeve bearings with oil cups but I had a friend bore out the two locations and press fit two ball bearings which is so much better. I can't imagine it being too difficult to change the bearings per original if you have an arbor press and can find the right bearings, but I'm no expert. Good luck!

Hello George, I restored my Craftsman lathe, which is a 1938 model, and in doing so I found that Sears still has the bronze bushing available, so I ordered them on-line. It was a simple task to drive the old ones out of the head stock and press the new ones in. I also went directly to the oil cup manufacturer to get new cups (the old were smashed) of similiar design to the original ones. After sandblasting the iron and hand scraping the ways I had a local paint supplier mix a quart of the original blue paint. This was a ground-up restoration project, as I acquired the lathe for $5 (along with two dead motors and a similiar era very deep throat scroll saw which is laying in my workshop awaiting a need for me to do something with it). I will attempt to add a parts list and some photos of my lathe to this posting, but I am not positive that I know how, but I could send them via e-mail if you would like to see them.