Zbag, I want to say it's a bad bet based on your odds, but one site tells me differently.
If you win in two years, you will have won with odds of 250:1 (if my math is correct). Current odds I saw at one site have the Cats in the Final Four at 125-1. DePaul is at a more realistic 250-1, and I saw Loyola at 250-1.
So according to the site, you got good odds. But I'd probably EASILY take higher odds and still bet against them.
I have no clue of your age, but let's say you're 30. If you win in 15 years (maybe 16 years if you want to be specific), you won $5000 vs. $600 - or a little more than 16:1.
If you win in 60 years at the age of 90, your payout is $5000 vs $1200 - a little more than 4:1.
I'd easily make a 16:1 bet they dont win in 15 years also.
You need to renegotiate.
Anyhow, fun idea. Hope you win.