Any luck yet? You should be able to get spring kits from a local auto parts store still. The only self-adjuster kits I’ve seen are for 1964 on up, of course. I’ve seen early Corvair kits available on the web but they didn’t have a picture to compare the Olds parts with or they had a generic picture. I’ve never seen any NOS parts on ebay. If you can’t find anything you might try to get just one of the Corvair kits and compare it to the existing parts you have on the one wheel. Just a thought.