C'est avec cette monoplace que Scheckter remporte le Championnat du monde de 1979, plus grâce aux qualités du moteur qu'à celles du châssis, conçu pour exploiter l'effet de sol mais moins réussi que les châssis de ses adversaires .
   Villeneuve s'impose dans les deux premières courses de la saison (Afrique du sud et États-Unis Ouest) et gagne à nouveau le second GP américain, mais c'est Scheckter qui remporte le titre mondial grâce à ses victoires à Monaco, Zolder et Monza.

   In 1979, Ferrari brought in as its No. 1 driver Jody Scheckter, who had driven for Wolf-Ford the previous season. The South African and the Canadian Villeneuve proved the consummate GP tag team.
   “We weren’t just teammates,” Scheckter recalled in Ferrari 1947-1997, “we were friends and wanted to work together to win races, so we made an agreement to share all our technical information.”
   The arrangement worked quite well, indeed. The duo finished 1-2 in the debut of Ferrari’s new car, the 312 T4, in South Africa for the season’s third race. The T4 represented Ferrari’s transition from mere areo design to true ground effects, in which the car’s structure and shape managed airflow along the sides and underbody to generate maximum adhesion.
   Each the winner of three races, Scheckter was World Champion, Villeneuve was runner-up, and Ferrari handily won the makes title, its fourth in five years.
   The next season saw the final development of the 312 series, the 312 T5. Bodywork was once again modified, but the rapidly changing science of ground effects had moved beyond what Ferrari could do with its flat-12 engine, a powerplant that was wider and thus more difficult to package in terms of airflow management than the Ford-Cosworth V-8 that powered Alan Jones and his Williams-Ford to the championship.