The 158 was powered by a 1.5-litre V8 engine with a bore and stroke of 67.0 mm by 52.8 mm. Unusually for Ferrari at the time, the car used a monocoque chassis construction rather than a spaceframe, reflecting the direction the rest of the grid had been moving since the early 1960s. The V8 produced 210 PS at 11,000 rpm.
Ferrari complemented the 158 with a second car built on the same chassis but equipped with a flat-12 engine, designated the Ferrari 1512 (also known as the Ferrari 512 F1). The flat-12, designed by Mauro Forghieri, displaced 1,489.63 cc and developed 220 PS at 12,000 rpm, making it one of the most powerful 1.5-litre engines of the era, second only to the Honda RA271 V12. Three 1512 chassis were produced, numbered 0007, 0008 and 0009. The 1512 was intended for use on the longest, fastest circuits — Reims, Spa, Monza — while the lighter, more agile V8-powered 158 was better suited to slower, more technical venues. The 1512 made its racing debut at the 1964 United States Grand Prix at Watkins Glen.
John Surtees drove the 158 to win the 1964 World Championship under deeply unusual circumstances. Ferrari's relationship with the Automobile Club d'Italia had deteriorated over arguments concerning the homologation of a new mid-engined Ferrari road car. In protest, Ferrari's official factory entry was withdrawn from the final two races of the season — the United States and Mexican Grands Prix — and the cars were instead entered by the NART team, a factory-supported but nominally independent American outfit. To underline the distinction, the cars were painted not in the traditional Scuderia Ferrari red but in white and blue.
The championship went to the final race in Mexico, where Surtees needed to finish second or higher while title rival Graham Hill took points away from him. Surtees finished second, giving Ferrari the Constructors' title and Surtees the Drivers' Championship by a single point over Hill and Jim Clark.
The flat-12 variant was raced alongside the 158 during the latter part of 1964 and into the 1965 season. Its power advantage on fast circuits gave Ferrari an additional tactical option, though the 1.5-litre formula was approaching its end; the regulations changed to 3.0 litres for 1966.
The Ferrari 158's significance lies in two areas: as the first Ferrari Formula One car built around a monocoque chassis, it marked a structural evolution for the Maranello team, and as the car that delivered Surtees his championship, it occupies a central place in both Ferrari's and British motorsport's history. Surtees remains the only person to have won World Championships on both two wheels and four.