CREATE TABLE table_name_98 (date VARCHAR(255), test_debut VARCHAR(255), position VARCHAR(255), year VARCHAR(255))
What date has a Position of back, later than 1964, and a Test debut of 1st rl test v new zealand?
    
SQL: SELECT date FROM table_name_98 WHERE position = "back" AND year > 1964 AND test_debut = "1st rl test v new zealand"