1967–1968

Debuting in 1967, the groundbreaking Miura (foreground) became Lamborghini's first mid-engined two-seater

Production of the 400GT continued, with Ferruccio Lamborghini seeking to replace the four-year-old design. Lamborghini commissioned Touring, which had styled the 350GT and original 400GT, to design a possible replacement based on the same chassis. Touring's 400 GT Flying Star II did not win Lamborghini's approval. Giorgio Neri and Luciano Bonacini, of Neri and Bonacini coachbuilders in Modena produced their own design, the 400GT Monza, which was rejected as well.^[34] Facing mounting financial difficulties, Touring would close its doors later that year.

The Islero was a sales disappointment, but faithful to Ferruccio's ideal of a reliable grand tourer.

Ferruccio Lamborghini turned to Bertone designer Mario Marazzi, who had formerly worked at Touring. Together with Lamborghini's engineers, he created a four-seater named the Marzal. The car rode on a stretched Miura chassis, and was powered by an in-line six-cylinder that was made from one-half of Lamborghini's V12 design.^[35] Despite an innovative design that featured gullwing doors and enormous glass windows, Lamborghini rejected the design. Eventually, a toned-down version became the Islero 400GT. While the car was not the full four-seater that he desired, Ferruccio Lamborghini thought the car represented a well-developed gran turismo product.^[36] It failed to attract buyers, with only 125 cars produced between 1968 and 1969.^[37]
New versions of the Miura arrived in 1968; the Miura P400 S (more commonly known as the Miura S) featured a stiffened chassis and more power, with the V12 developing 370 bhp at 7000 rpm. At the 1968 Brussels auto show, the automaker unveiled the Miura P400 Roadster (more commonly the Miura Spider), an open-top version of the coupé. Gandini, by now effectively the head of design at Bertone, had paid great attention to the details, particularly the problems of wind buffeting and noise insulation inherent to a roadster.^[38] For all of Gandini's hard work, Sgarzi was forced to turn potential buyers away, as Lamborghini and Bertone were unable to reach a consensus on the size of a theoretical roadster production run. The Miura Spider was sold off to an American metal alloy supplier, who wanted to use it as a marketing device. 1968 was a positive time for all of Ferruccio's businesses, and Automobili delivered 353 cars over the course of the year.^[38]
In August 1968, Gian Paolo Dallara, frustrated with Ferruccio Lamborghini's refusal to participate in motorsport, was recruited away from Sant'Agata to head the Formula One programme at rival automaker De Tomaso in Modena. With profits on the rise, a racing programme would have been a possibility, but Lamborghini remained against even the construction of prototypes, stating his mission as: "I wish to build GT cars without defects – quite normal, conventional but perfect – not a technical bomb.^[39] With cars like the Islero and the Espada, his aim to establish himself and his cars as equal or superior to the works of Enzo Ferrari had been satisfied. Dallara's assistant, Paulo Stanzani, replaced him as technical director.^[40]