There's no single "average SAT score for minorities" because the term "minorities" encompasses a vast and diverse population with differing ethnicities and socioeconomic backgrounds, all of which significantly impact SAT scores. SAT performance varies considerably among different minority groups. You would need to specify the particular minority group to get a meaningful average. Furthermore, averages can be misleading and mask significant disparities within those groups.
To find data, you'd need to look at reports that break down SAT scores by specific ethnicities (e.g., African American, Hispanic/Latino, Asian American, Native American) from organizations like the College Board (which administers the SAT). Even then, remember that these are averages and individual scores vary widely.