Triumph realised that they needed to find an answer to the handling problem, if only to maintain their reputation in the U.S. Their response came with the 1969 model year, with the introduction of the GT6 Mk II, known in the States as the GT6+. The rear suspension was significantly re-engineered using reversed lower wishbones and Rotoflex driveshaft couplings, taming the handling and turning the Triumph into an MGB beater. The Vitesse was also modified, but the Spitfire had to wait until 1970 for any improvements to be made.

There were other changes for the Mk II; the front bumper was raised (in common with the Spitfire Mk 3) to conform to new crash regulations, necessitating a revised front end, and side vents were added to the front wings and rear pillars. Under the bonnet, the engine was the uprated Vitesse MkII unit developing 104 bhp (78 kW) with a new cylinder head, camshaft, and manifolds.[1] The major changes were altered valve timing and larger inlet valves, with an increase to the width of the head. Performance improved slightly to 107 mph (172 km/h), but perhaps more noteworthy the 0–60 mph (97 km/h) time dropped to 10 seconds.[1] The fuel economy was also improved to 25 mpg‑imp (11 L/100 km; 21 mpg‑US) average.[1] The interior was updated with a new dashboard and better ventilation, a two-speed heater fan and a black headlining. Overdrive remained a popular option for the manual transmission with the same specifications as the Mk I.