Two different engines used in this tractor were the K361 and the M18. You can still get a shortblock for the M18 engine or you can buy the 24302 and change your flywheel to make it work. The K361 engine was very poorly designed OHV engine. The heads normally did not last because of the unleaded gasoline running hotter than the head could stand. The replacement for this engine is the K341-71179 engine. This is not an OHV engine. You will have to reroute the muffler because of the angle on the block where this comes out. This tractor uses a 1-1/8" shaft on it. If your tractor has a K361 in it you can use our 350447-Ariens-GT16 conversion kit. If you use our Vanguard conversion kit in this tractor, you may have to notch out around the starter for it to sit down in the frame.