Someone asked me why my 69 R/T drums were painted red... my answer was, because that's what they did in the 60s. Well, here is the bona fide legit answer from Hot Rod's Steve Magnante:
"Starting with the 1968 Plymouth Road Runner and Dodge Super Bee, cars equipped with drum brakes and Magnum 500 or Rallye Wheels (1970-up) got a splash of red paint. Emulating a popular trend among the hot rod set, only the vertical faces of the drums were painted by assembly workers, with a brush no less. Many restorers erroneously cover the entire drum with red paint."