What is the best source for this in your view?

The raw data is plentiful -- look at any standardized test scores (e.g. SAT) by race. For a full-blown argument in favor see e.g. this (I can't check the link at the moment, it might be that you need to go to the Wayback Machine to access it). For a more, um, mainstream discussion see Charles Murray's The Bell Curve. Wikipedia has more links you could pursue.

Is it your view that past slavery in America still has a large impact on African Americans in the present day U.S.?

My view is that history is important and that outcomes are path-dependent. Slavery and segregation are crucial parts of the history of American blacks.

open to learning

Your social circles might have a strong reaction to you coming to anything other than the approved conclusions...