Giovanni Michelotti was commissioned by Standard-Triumph in early 1963 to design a GT version of the recently introduced Spitfire 4. Michelotti's design studio in Italy received an unmodified Spitfire 4, and late in 1963, the prototype Spitfire GT4 was returned to England for inspection and evaluation. The styling was very appealing but the Spitfire engine and extra weight of the GT bodyshell resulted in extremely poor performance. Plans for producing the Spitfire GT4 were shelved until a suitable powerplant could be sourced. Thankfully, the 2-liter 6-cylinder engine from the Triumph Vitesse proved adequate, and with further development and refinement, the Triumph GT6 was introduced. The 'GT' was in recognition of its styling and the '6' was for the six-cylinder engine.
The LeMans Spitfires and the GT6 were separate development programs, however, period Triumph marketing advertisements claimed the GT6 was a development from the 'race winning Le Mans Spitfires.' Nevertheless, the marketing spin proved very successful as many people erroneously believed the Le Mans Spitfires to actually be GT6s.
The Triumph GT6 arrived in October of 1966 and remained in production until 1973. Its chassis and running gear were essentially from the Triumph Herald that had proven more than adequate to cope with the six-cylinder power. The GT6 used the Herald/Spitfire's softly sprung rear swing axle that was later replaced by lower wishbones on the GT6 MK II (GT6+ in the U.S.), introduced for the 1969 model year. Additional changes introduced for the Mk II was a raised front bumper in compliance with safety regulations, a revised front end, and side vents added tot he front wings and rear pillars. The Vitesse MkII unit received a new cylinder head, camshaft, and manifolds resulting in an increase in horsepower to 104 bhp. The Zero-to-sixty mph time dropped to 10 seconds and the top speed increased slightly to 107 mph. The interior received a two-speed heater fan, black headlining, and a new dashboard and better ventilation.
The 1970 model year brought about the GT6 MkIII, the final major updating for the series. The changes made up to this point o the Spitfire Mk IV were now implemented on the bodyshell of the GT6. The changes included a cut-off rear end, a smoother front end, and recessed door handles. Near the end of production, the rear suspension was again modified, this time with a 'swing-spring' layout found on the Spitfire Mk IV. A brake servo was added in 1973, and the seats were changed from vinyl to cloth. Knock-on wire wheels no longer appeared among the list of options.
The engine of the MK II was used for the MK III with similar horsepower output, however, the top speed increased to 112 mph due to better aerodynamics. Acceleration was quicker and fuel economy improved. In the U.S., due to a shift to SAE net figures, horsepower ratings declined, dropping to 79 bhp for 1972 and 1973. Overdrive could now be selected at the gearshift lever rather than its prior location on the dashboard.
In the U.S., the 1972 Triumph GT6 MkIII Fastback Coupe had a base price of approximately $3,375.By Daniel Vaughan | Jul 2020