Without taking exact measurements, it looks possible for the rear plastic from an '05-later 500, 650, and 700 to fit on the frame of an '06-later 400. The only place they touch is where the rear rack mounts, where the fuel tank comes through the body, and where the floorboards attach. The floorboards are different part numbers for the 500 and 400. However, they appear to attach to the rear fender panel identically. If they don't bolt up directly, it wouldn't take much modifications to make it work. :kewl: