I figured I would circle back and update this one. I started another thread to try and figure out the deck drive belt situation, and I found that the 81" belt the manual calls for is the right one. Somehow I ended up with two mutant belts that don't fit, and they both came off applications that look to me like they call for the same belt. That's kind of how the story goes for me, but now I can mow with it.
