Ferrari 643 current version 0.5

The Ferrari 643 was a Formula One car designed by Steve Nichols and Jean-Claude Migeot and was built by Scuderia Ferrari for use in the 1991 Formula One season. Built during May and introduced at the French Grand Prix, it initially looked to have potential to run at the front. Alain Prost qualified on the front row and took the lead, and although he was eventually passed by Nigel Mansell in his Renault powered Williams FW14, a second place in the car's first race looked promising. Aside from almost always being on the front part of the grid, it was not to be however.

The chassis of the 643 was a total redesign over the 642 which suffered inconsistent handling issues, and was designed to allow for a more softer suspension travel, as per Prost's request. The car also featured Ferrari's first 'raised nose' design which allowed better airflow underneath the car. The V12 engine was upgraded six major times during 1991, with the final evolution used from Portugal to the end of the season. The chassis itself had two revisions, the first after the French Grand Prixwhich saw a relocation of the exhaust exits from underneath the car, and Belgium which saw minor alterations to the body cover.

Although arguably one of the prettier cars in the field, the car was not as competitive as the Williams and McLaren cars of 1991.A big problem with the car lay with a lack of correct data gathering due to the team's turbulent management structure at the time. The car's results (or lack thereof) was one of the main reasons for the falling out between Prost and Ferrari, with the Frenchman eventually saying that 'a truck would be easier to drive than this car'. Following the Japanese Grand Prix, Prost was fired for the second time in his F1 career by a works team. The team replaced him in Australia with test driver Gianni Morbidelli.