gwest_ca-(File Mod) 11,512 #1 Posted October 21, 2012 Go to https://lookup3.toro.com/partdex/index.cfm?xCaller=Toro and type in 520-H. They will all come up with what Toro is looking for a serial number. The word none is used for a serial number for 1990 and older product. Some of the 520 serial numbers are 1 digit short on the tractor decals so add a zero at Toro if it does not work. Garry Share this post Link to post Share on other sites