CREATE TABLE table_58648 ("Season" FLOAT, "Date" TEXT, "Winning Driver" TEXT, "Car #" FLOAT, "Sponsor" TEXT, "Make" TEXT, "Distance" TEXT, "Avg Speed" TEXT, "Margin of Victory" TEXT)

What is the highest car number sponsored by Post-It / National Guard?
SELECT MAX("Car #") FROM table_58648 WHERE "Sponsor" = 'post-it / national guard'
SELECT MAX("Car #") FROM "table_58648" WHERE "Sponsor" = 'post-it / national guard'