One of the most famous Rover V8 rebuild projects, one that has itself become a part of British motoring history, is using the famously versatile and reliable engine to fix one of the greatest mistakes of one of Britain’s most beloved cars.

The Triumph Stag is a quintessential example of the British sports car; a beautiful soft-top convertible that was remarkably innovative for an early 1970s car by British Leyland, and quickly became a sales hit.

However, it would quickly develop a truly abominable reputation, which meant that just over 25,000 cars were sold in seven years.

Why was it a sales failure? The simple answer was that it used the wrong engine.

What Was Wrong With The Triumph Stag’s Engine?

The Triumph Stag used a thankfully unique V8 engine, made by bolting together two 2.0-litre slant-four engines.

The base engines themselves were perfectly capable, having been used in the Saab 99 and the Dolomite Sprint, but putting them together opened a Pandora’s Box of reliability problems.

Of the many problems with the Triumph V8, by far the largest of which was a long single-link timing chain, which often broke under the slightest tension.

Add to this warped cylinder heads, poorly sized main bearings, unreliable water pumps and poor cooling in general, and the car had a disastrous launch in America, limiting its potential.

Why Did The Triumph Stag Not Use The Rover V8 Engine?

The greatest “what-if” question in British motoring history is why the Stag did not use the Rover V8, as the TR8 which replaced the Stag ultimately did. Many enthusiasts have proved it would fit with little modification and significantly improve the experience.

There have been many reasons, from claims it did not fit (proven to be untrue), concerns with Buick’s lack of experience in the UK market, worries that the Rover V8 required an automatic transmission and concerns about supply numbers.

Ultimately, the real reason was most likely timing; Leyland bought the Rover Company in 1967. By this point, the Triumph V8 engine was already far enough that there was a sunk cost fallacy and a degree of company pride which led them to stick to their guns.