↑The 1973 Matchbox Collectors Catalogue shows the Y-8 Stutz in blue, however the Kevin McGimpsey & Stewart Orr book Collecting Matchbox Diecast Toys - The First Forty Years, First Edition, 1989, page 186 states that the blue version was introduced in 1974.
↑ 3.03.1Kevin McGimpsey & Stewart Orr, Collecting Matchbox Diecast Toys - The First Forty Years, First Edition, 1989, pages 185-186