Selmer Signets of course will fit too. I swapped a neck from a Signet to a Bundy, big improvement in sound. But Ed is right, you're better off with trying to find another Bundy. Often, a complete Bundy will be available for next to nothing on Ebay. Usually the sax is pretty beat, but you only need the neck, right ? Plus side is, you'll have a spare sax for any possible parts you might need later. However, Bundys are known for being rather solidly built, so replacement parts probably won't be something you'll need much of, if ever.