 An all-new TR7, with a unit body, an overhead camshaft four-cylinder engine, and a live rear axle, was introduced in late 1974.The TR8, a development of the TR7 with a Rover V8 engine, was introduced in 1979 and was sold alongside the TR7 until TR production ended.The Triumph TR-X, also known as the "Bullet", was the first Triumph car to use the TR designation.