In 1964, The Cavaliers added mellophones and contrabasses to their horn line. The 1966 drum line is still considered to be one of The Cavaliers' best, and it propelled the corps to the American Legion Nationals crown. 1967 saw Cavalier Hall, the first corps hall in the activity, go up in flames, taking the corps' trophies with it. 1967, too, was the first time in eighteen years that the Cavaliers did not include "Somewhere Over The Rainbow" in their musical program. They also won the VFW Nationals, then repeated as American Legion Champions. The high of 1967 was followed by a 1968 where nothing was just quite right, and the corps finished second at VFW Nationals. The corps rebounded in 1969, winning the American Legion title, and barely losing VFW to the Kilties. Probably the highlight of 1970 was the Cavaliers' rise from eleventh place at VFW National prelims to third place in Finals. Overall, the "Green Machine" of the 1960s won three American Legion and four VFW National Championships, and did not finish lower than third place in sixteen national finals competitions (VFW, American Legion, and CYO).