CREATE TABLE table_21977704_1 (no INT, entrant VARCHAR, driver VARCHAR)

Name the most number for autom vil club argentino for benedicto campos
SELECT MAX(no) FROM table_21977704_1 WHERE entrant = "Automóvil Club Argentino" AND driver = "Benedicto Campos"
SELECT MAX("no") FROM "table_21977704_1" WHERE "Automóvil Club Argentino" = "entrant" AND "Benedicto Campos" = "driver"