In Tome of Magic, the Murder of Crows monster can be an Unkindness of Ravens - with the same stats.
I think it's fairly safe to say that in D&D, crows and ravens use the same basic statblock.
And in real life - there's nothing really distinguishing them except size. The smaller ones are more likely to be called crows, but those ones are often closer related to ravens than to one another.
The pied crow, for example, is genetically closer related to common ravens than to anything else. In fact, it is nested within the common raven complex - any clade that includes all common ravens will included pied crows as well.