The older issues of Statistical Abstracts of the United States have most of the data you want. Here is the link to 1951-1994: www.census.gov/prod/www/abs/statab1951-1994.htm. Each report will have data for a couple of years earlier; e.g., the 1951 report has data for 1949. You'd need to scroll through each year to find the relevant data. For example, the 1951 report has chart on "Felony Prisoners by Color, Nativity, Age, and Sex". (nativity being whether they were born in the U.S. or not)
The census has a chart of federal and state prisoners, by sex, 1925-2001.
www.census.gov/statab/hist/HS-24.pdf
Lastly, this report, called "Changing America: Indicators of Social and Economic Well-Being by Race and Hispanic Origin" (www.access.gpo.gov/eop/ca/pdfs/ch7.pdf) has on page 55 (page 6 of the PDF file) a graph of the numbers of whites and blacks in prison from 1930-2000. You'd have to estimate from the graph, as the numbers aren't written on it.