Try to search yahoo or google for whichever model he wants. The best option is ebay man, theres always pre raced 440's and stuff for sale on there, in fact i think theres a mxz 440 and an iq 440 race sled on there right now.
Go to your local races for sure there should be some for sale. Talk to some people there and see what you can find. You need to be very careful when buying one because of the amount of abuse these sleds take. Make sure to inspect them very carefully.
My friend had the exact same problem. What he did was to look at the auto trader magz in the private sections and look for sleds there. But in the end he found a sled because he went to his local snowmobile shop where racers tune their sleds up and thats where he found one. You best bet is to talk or buy something from someone who is around race sleds alot . Going to a track and asking racers in person is probably the best thing to do if you are relitivley near one. Other than that i think your best bet is to go to a local shop and ask them there or simply put out a flyer.
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