The Triumph TR8 is essentially a V8 version of the Triumph TR7 that was produced in limited numbers, and almost all of them were sold in either the United States or Canada. Engineers at Triumph had been working on a V8 TR7 since the early 1970s however MG and Range Rover had first priority for Rover V8 engines. The Rover V8 was still relatively new in Britain at the time, it was based on the earlier Buick 215 cu. in. all-alloy V8 that had been discontinued in the 1960s. The decision to use the Rover V8 was a little controversial as in the 1960s Triumph had spent a lot of money developing their own V8 engine. Triumph engineers had taken their own pre-existing inline-4 and developed an engine block that could accomodate two of them in a V-configuration, creating a V8. Unfortunately the development process was rushed and the resulting engine was hugely problematic, it was clear that fixing it would have cost a fortune.
The Triumph TR8 first went on sale in 1978 however by this time the company had already built 145 Rover V8 powered TR7s for testing and evaluation purposes – possibly to absolutely ensure everything was working properly considering their bad luck with their previous V8 project. The lightweight 3.5 litre aluminum V8 fit snugly into the TR7 engine bay, it was mated to a five-speed transmission and sent power back to a live axle. With a curb weight of 1,204 kgs (2,654 lbs) and 148 bhp at 5100 rpm in fuel injected form, the TR8 could deliver 0 to 60 mph times in the low 8 seconds.