the twin Solex carburettors were replaced by twin Stromberg CD 150 carburetors. Power output increased from the original at 5,000 rpm and torque of . There was a claimed increase of 13–14 bhp, and the motoring magazine tested top speed rose to , with the time decreasing from 46.6 seconds to 33.6 seconds. The Vitesse 6 sold extremely well for Triumph, proving to be the most popular Vitesse sold during the model's lifetime. The car received initial praise for its performance, fuel economy, interior and tight turning circle. Sports 6 The Vitesse 6 convertible was exported to the US as the left-hand drive Triumph Sports 6 from 1962 until 1964. Original US price (POE East Coast) was $2,499, and it was offered in White, Signal Red or Black. The Vitesse Saloon was never officially imported to the US. Due to its high retail price and competition from cars such as Ford's new Mustang, only 679 were sold before it was withdrawn from the market. Vitesse 2-Litre In September 1966, Triumph upgraded the engine to 1998 cc, in line with the new Triumph GT6 coupé, and relaunched the Vitesse as the Vitesse 2-Litre. Power was increased to , endowing the new car with a claimed 0–60 mph time of just under 12 seconds, and lifting top speed to . (The 2-Litre was advertised by Triumph as "The Two Seater Beater"). Other detail modifications for the 2-litre included a stronger clutch, all synchromesh gearbox, larger front brakes, and a stronger differential with a slightly higher 3.89:1 ratio. Wider & stronger 4.5-inch wheel rims were fitted, but radial-ply tyres were still optional at extra cost. There was a satin silver anodized aluminium-alloy cowling above the new reversing light, and badges on the side of the bonnet and in the centre of the grille read 2 litre. The Vitesse boot badge was retained as italic script but lost the 6 of the earlier model - replacing that with the rectangular 2 litre badge and with a chrome strip underlining the Vitesse badge. Cars with overdrive had a separate badge on the cowling above the number plate/reversing light. Inside the car, the seats were improved, with softer (more plush) covering and a better back-rest shape which slightly improved rear-seat knee-room. A new leather-covered three-spoke steering wheel was also added. The Vitesse Mk I was sold until 1968. Vitesse Mk II The Vitesse Mark 2 was