Mk3 : The Spitfire Mk3 was instantly recognisable by its raised, 'bone in the teeth' front bumper.

The much-improved Mk3 went into production early in 1967. It did not go on sale in the USA until March of that year.
The most obvious outward change was the 'bone-in-the-teeth' raised front bumper, introduced to comply with American safety legislation. Most important change, though, was the new 1,296cc engine, which produced a healthy 75bhp. The increased capacity was achieved by enlarging the cylinder bore from 69.3 to 73.7mm. Minor changes were larger front brake calipers, a larger 15" steering wheel as used in the TR4, a wood-veneer dashboard, different seats and the fact that the electrics of the car were now negative earth.

The 100,000th Spitfire to roll off the production line on 6 February 1968 was a Mk3. Due to ever-increasing mutterings of both customers and the motoring press about the build-it-yourself convertible top, the Mk3 came with a new, much improved folding softtop. This no longer needed stowing in the boot, but was more or less permanently attached to the car. Equally increasing criticism of the somewhat 'exciting' handling, due to the swing axle rear suspension, wasn't dealt with until the advent of the MkIV. It did not prevent the Mk3 from being popular with the racing fraternity. Especially its free-revving and powerful engine made it eminently suitable for the track. Many American owners installed a 'camber compensator' to make the car less of a handful on corners.
Total Mk3 production would eventually reach more than 65,000.

British Leyland : In January 1968 Leyland Motors, the company that had been the owner of Standard-Triumph since 1961, took over British Motor Holdings, which included Jaguar, Daimler and the whole of the BMC company, including Austin, Morris and MG. The merged company was rechristened British Leyland.
One of the results of this merger was that competing sports cars (Triumph Spitfire and the Midget/Sprite range from MG and Austin-Healey) were now built by the same company.