1968 Triumph TR250

For the 1968 model year, Triumph released the TR5, which was basically a TR4A with the 2.5L pushrod inline six developed for the forthcoming TR6 shoehorned into the engine bay. This bumped horsepower by almost fifty percent, to 150, versus the previous 105-horse 2.1L four cylinder, which had begun life as a propulsion unit for Ferguson tractors.

But 1968 saw the dawn of ever-tightening emissions regulations in America and the new fuel-injected, 9.5:1 compression, 2.5L straight six would be tough to bring into compliance. (To say nothing of the cost bump, estimated at as much as $600, on a car that cost under $3,500.) So the US market got the TR250, with a pair of Zenith-Stromberg carbs and an 8.5:1 compression ratio instead.

This cut horsepower from 150 to 111 on U.S.-market cars. Performance took a hit, understandably. While the fuelie motor in the TR5 would clock a 16.5 second quarter mile on its way to a 118 mph top speed, Road & Track only managed a 17.8 second quarter and clocked 107 mph on the top end with their test TR250.

The Triumph inline six was a big improvement over the four cylinder tractor motor it replaced, but it still displayed a very British quirk. With a 74.7mm bore and a 95mm stroke, it was decidedly undersquare. This is because motor vehicle taxes in the UK were based on piston area, so adding displacement by lengthening the stroke hurt customers wallets less than enlarging the bore would have.

Priced at $3,395, about $30,650 in 2024's money, Triumph managed to sell 8,484 TR250s before it was replaced with the TR6 for 1969. An estimated 1,300 remain roadworthy.

This example was snapped in Indianapolis in October of 2020 using a Nikon D7000 and 16-80mm f/2.8-4E VR zoom lens.