Complex sentence: In the late 1960's and the 1970's Mr. Raper danced in over 400 swing dance contests, including the 1973 World Swing Dance Championships at the Palladium in Hollywood, CA.
Split into simpler sentences: In the late 1960's and the 1970's he became heavily infolved in swing dance. He danced in over 400 swing dance contests, including the 1973 World Swing Dance Championships at the Palladium in Hollywood, CA.