This is a pre-production prototype that was scheduled to be released for the 1982 model year. Is vin numbered as a 1981 model. Has a 500 fan cooled engine with many signs of being a pilot build...oil-injection, dual carbs, 1st generation plastic cooling shroud, hand stamped i.d. number, etc. Has an 82 only hood, nose cone, console, fiberglass belly pan, seat, etc. I bought this in 1991 from a dealer that had gotten it from Arctic. It took 18 years to finish this as I was always needing some part that I couldnt find. Just about 2 decades later and the restoration/preservation of this snowmobile is done!