The 33TT12 and the 33SC12 Turbo were by far the most dominant of the 33 family, with each handily winning a World Championship for Makes. It wasn’t immediate though. The 33TT12 (“TT” designating Telaio Tubolare, “tube frame,” the “12” for the new three-liter flat-12 mounted behind the driver’s head and under that towering induction scoop), began its competitive life in 1973, but seeing as it was basically an entirely new car, the season’s efforts did not result in any wins or much success, with a few crashes and a slew of retirements. The TT12 was still being honed in 1974, and it finally saw victory at the Monza 1000km with Mario Andretti and Arturo Merzario driving.
1975 was the banner year for the TT12; further tuning had bumped its power past the 500 mark for the first time, and it was the year that would finally give Alfa the Makes title in the WSC. And it did so with ease – the TT12 won seven of the eight races in the season, as well as another overall win at the Targa Florio on top of that.
The 1976 season saw the TT12’s replacement being developed: the SC12 (“SC” for Scatolato, “box-section,” or “monocoque”), a lighter, stiffer, faster car altogether. The reason for its existence was mainly due to to the tube-framed TT12 not being able to cope with the ever-rising power of Carlo Chiti’s flat-12 (around 520 by the time it found itself in the new SC12), and the effort proved to be worthwhile, seeing as the SC12 won all eight races in the championship season of 1977. As all of this was going on, Alfa and Autodelta were working on a twin-turbocharged version of the flat-12 (even back in 1976 while the NA car was still being put together), and before the 33 program would cease in order to allow the company’s pursuit of Formula 1 they completed a 2.1-liter flat-12 with a turbocharger for each bank of cylinders. It produced a staggering at the time, and now, 640hp. The 33SC12 Turbo was only entered in two races in ’77 season, in which it claimed a second and first, at the Salzburgring and Hockenheim, respectively.