SELECT "Winning driver" FROM table_4767 WHERE "Winning team" = 'chaparral' AND "Name" = 'indianapolis 500'
Which driver won the Indianapolis 500 the year the Chaparral team also won it?
CREATE TABLE table_4767 (
    "Name" text,
    "Pole Position" text,
    "Fastest Lap" text,
    "Winning driver" text,
    "Winning team" text,
    "Report" text
)