The TR5, also known as the TR250 in the United States, was introduced in 1967 as the successor to the TR4A. It featured a 2.5-liter straight-six engine with fuel injection, making it one of the first British production cars to use this technology.The TR6, introduced in 1969, continued the Triumph tradition of two-seat roadsters. It featured a 2.5-liter straight-six engine, but unlike the TR5, it used carburetors instead of fuel injection. The TR6 retained the classic body-on-frame construction and featured a restyled body with a distinctive Kamm tail.

The TR250 was essentially the North American version of the TR5, featuring the same 2.5-liter straight-six engine with fuel injection. Due to emission regulations in the United States, the TR250 used twin Zenith-Stromberg carburetors instead of the Lucas mechanical fuel injection used in the TR5.

These Triumph TR models, particularly the TR5 and TR6, are well-regarded among classic car enthusiasts for their styling, performance, and driving experience. The transition from the TR5 to the TR6 marked an evolution in design and technology while maintaining the classic British sports car appeal.