You mean back when Americans of all ages voted along class lines (somewhat) and working class people couldn't attend universities unless they'd had a military career before?
Of course, there were plenty of elite Democrats back then ("before the 70s" is an awfully long time), and there have always been certain working-class areas that voted heavily Republican (some since the Civil War era)....
What are some working-class areas that were Republican in the 30's-40's era?
Eastern Tennessee.
Eastern TN, South Central KY (and East KY before the New Deal), certain rural parts of the Midwest (usually on a north south divide as well with the rural areas in the more Southern parts being Democratic and the northern parts more Republican), NY, PA, and New England. A lot of that has to do with settlement patterns, legacy voting dating back to the pre-Civil War and cultural inclincations.
