- 5,303
- Riverside, Ca
- GTP_Leonidae_MFT
The final major facelift for the GT6 came in 1970, to make the MK3. This time the whole bodyshell was revised to match the changes made to the Spitfire Mk IV; these included a cut-off rear end, recessed door handles and a smoother front end. Only detail changes were made to the mechanics, but in 1973 – close to the end of the car's production life – the rear suspension was changed again, this time for the cheaper (but still effective) "swing-spring" layout also fitted to the Spitfire Mk IV. This was a modification of the swing axle rear suspension used on the lesser Herald-derived models, with the transverse leaf spring mounted on a pivot, eliminating roll stiffness at the rear, and thus greatly reducing the jacking effect under cornering loads. To compensate for this loss of roll stiffness, a larger front anti-roll bar was fitted. A brake servo was also added in 1973, and seats were changed from vinyl to cloth. There was still a fairly comprehensive options list, but the "knock-on" wire wheels were no longer available. The unladen weight increased slightly to 2,030 lb (920 kg).[1]
Engine power and torque for the Mk III was similar to the Mk II, but better aerodynamics led to a new top speed of 112 mph (180 km/h) and a 0–60 mph time of 10.1 seconds;[1] this was now comfortably ahead of the MGB GT, which topped out at about 105 mph (169 km/h) and reached 60 mph in approximately 13 seconds. Fuel economy was also improved to 28 mpg-imp (10 L/100 km; 23 mpg-US).[1] The last USA models performed comparatively poorly however, as compression ratios were lowered to accommodate lower octane unleaded gasoline.
The Mk III never sold in the numbers hoped for by Triumph, and was comprehensively beaten in the marketplace by the MGB. Triumph refused to release an official convertible version of the GT6 and, after poor sales, it was dropped from the Triumph range at the end of 1973, although a few cars were sold the following year.
