Thought would start a new thread. No. Can't find article in hook about 320 upgrades. Maybe someone here can remember it. But have a friend who has a big one. His smaller one won the 4250 king of hill 5 mph at Tunica. This month. So much for spinning your tires slow! Yes have both the 435 and the D17 running. Took the D17 to Tunica. Never placed. Not the Tractors fault. I was to heavy on front. Then to light. After 4 pulls finally got it close. Also the rear tires are to far apart. Moving them together now. 22". Maybe can drive it then. But it has plenty of power for now.