My dad had this exact machine when I was little, and I have another one in my own collection. The 318 cc engine had a high compression ratio and was rated at 18 hp, which seemed pretty zippy compared to the very popular 12/3 Olympiques. In my experience that engine needs premium gas to keep it from pinging.
That intact carb box with the Bombardier badge still on it (!!!) can bring $200 alone. Rare to see the plastic belt guard still in place as well. Original seat too!
Common problems: The track and track sprockets on Ski Doos of this vintage seem to falling apart at this point in history. The built-into-the-chassis gas tank can be filled with varnish or rust.
I see these (in barn-find condition) generally trade in the ~$300 range, usually without the carb box, so figure that into your price.