Complex sentence: She competed in the 1969 and 1970 U.S. Nationals in a twin-engine dragster in the Top Gas classification, but with Top Gas losing popularity, switched to Funny Car, buying her first ride from Connie Kalitta.
Split into simpler sentences: She competed in the 1969 and 1970 U.S. Nationals in a twin-engine dragster in Top Gas. With Top Gas losing popularity, Muldowney switched to Funny Car, buying her first car from Connie Kalitta.