Table schema:
CREATE TABLE table_name_81 (crew_chief VARCHAR, primary_sponsor_s_ VARCHAR, car_s_ VARCHAR, team VARCHAR)

Question: Who is the crew chief of team Joe Gibbs Racing, which has a Chevrolet Monte Carlo and Fedex as the primary sponsor?
SQL: SELECT crew_chief FROM table_name_81 WHERE car_s_ = "chevrolet monte carlo" AND team = "joe gibbs racing" AND primary_sponsor_s_ = "fedex"