In a search for greater power and refinement, Triumph dropped a long-stroke version of its six-cylinder engine into the TR4A body and created the 2.5-litre TR5. Most of the world got the Lucas fuel-injected 150bhp engine. America was different. To get round emissions regulations Triumph sent them a twin-carb version with just 104bhp and called it the TR250. It sounds like a terrible idea, but these outsold the TR5 by almost three-to-one. It’s not unusual to find examples that have been repatriated to the UK and fitted with the injection engine from the much-less-valuable TR6.