The 580 Case series comes with either a 207 Case engine or a Cummins 239. The Case 207 is rated 55 net horsepower and the Cummins is 60 horsepower.
I'd be more concerned about machine weight and hydraulic power though. The horsepower doesn't have much to do with digging power.
Deere 401 or 410 is around the same engine power as a Case 580.