You do not want to use a CV belt drive system on a prop... CV's are meant for variable loads, a [fixed] prop is completely constant. They are also fairly inefficient, at least compared to a fixed belt/chain drive.
Anyway, you are going to want to look at a fixed belt drive system with about a 3:1 reduction. Dig around in the ultralight airplane communities, lots of those guys are using rotax engines that are relatively similar to snowmobile engines, at least in powerband/rpm. They will have suitable belt drive reduction systems.
1) 2000 Arctic cat ZR 700, which now thinks it is a 2001 ZR 600 EFI APV w/136" ripsaw. (for sale!)
2) 1995 Yamaha VMAX 600, which now thinks it is a Polaris! (Polaris x10 suspension, Polaris P85 clutch) (for sale!)
3) 2004 Yamaha Warrior
4) 2006 Yamaha Nytro