What engine do most rally cars use?

I'm curious, could you tell me what kind of engine is typically found in rally cars? I've always been fascinated by the speed and power these vehicles possess, and I'm eager to learn more about their technical specifications. Are rally cars known for using a particular type of engine, or do they vary widely in their engine choices? I'm especially interested in how these engines are optimized for the unique demands of rally racing, such as handling rough terrain and maintaining high speeds over long distances. Can you elaborate on the engineering behind rally car engines and how they differ from those found in other types of racing vehicles?