There was a used one I was looking at from a salvage yard, but it was still going to be around $2500 to get it shipped and installed and only would have been warrantied for 30 days so I felt like it might be better to just spend the extra to get the existing motor overhauled.
Then again, once it gets started it actually runs OK (or at least not noticeably worse than it has for years) and doesn't visibly smoke or anything, so if I can get it to start reliably in less than 3 tries maybe I'll just keep on truckin' and see if I can make it to 300,000...