user: Question: Which engine is responsible for the USAC Championship Car?
Columns: ['Season', 'Date', 'Driver', 'Chassis', 'Engine', 'Series', 'Report']
Types: ['text', 'text', 'text', 'text', 'text', 'text', 'text']
Sample row: ['1967', 'August 6', 'Mario Andretti', 'Brawner Hawk', 'Ford', 'USAC Championship Car', 'report']
SQL:

assistant: SELECT "Engine" FROM "Table" WHERE "Series" = 'USAC Championship Car';