CREATE TABLE table_56764 ("Driver" TEXT, "Constructor" TEXT, "Laps" FLOAT, "Time/Retired" TEXT, "Grid" FLOAT)

What is the grid total for bruce mclaren with over 73 laps?
SELECT SUM("Grid") FROM table_56764 WHERE "Laps" > '73' AND "Driver" = 'bruce mclaren'
SELECT SUM("Grid") FROM "table_56764" WHERE "Driver" = 'bruce mclaren' AND "Laps" > '73'