More than double the horsepower mainly due to turbo charging.
That level of power is for commercial use, an 11L diesel can easily put out more than 1000hp based on the amount of boost but the longevity of the engine suffers and the power is not need for the application.
Here is a Volvo 13L (The Mack MP7 is basically a Volvo D11) putting out 2500hp: https://www.motor1.com/news/94292/2400-hp-volvo-truck-seeks-...
As a comparison, here's a modern 11L diesel:
https://www.macktrucks.com/powertrain-and-suspensions/engine...
You'll notice that HP is 325-425, so not that dramatically different from the Snow Cruiser.