I'd keep it. If it has a 398, it is just that much more fun. I don't know if the snowmobile market is anything like the car market, where they want original everything. However, a guy was nuts for my 80 Citation SS and gave me his 96 Vmax that was in better condition, so who knows!
Honestly, I'd keep the sled. If you find a 295, you can always stuff it in there. Until then, have fun with it!