This is a de Havilland Turbo Beaver. De Havilland Canada delivered approximately 1,700 DHC-2 Beavers between 1947 and 1968. Sixty of those were Turbo Beavers sporting 550 hp P&W PT6A-20 turboprop engines. The first Turbo Beaver was delivered in January 1965. This DHC-2 Mk 3 Turbo Beaver was delivered to its first owner in June 1967. The fancy paint job was done this year. Not surprisingly, many of the amphibians at Oshkosh are of Canadian registry.
Here are the specs for the Beaver, Turbo Beaver, and other de Havilland Canada aircraft. Many of the Beavers flying today have undergone extensive upgrades. Two companies specializing Beaver and Turbo Beaver upgrades and conversions are Wipaire and Viking.