Only possible way to achieve smaller emissions and still deliver the same performanc as before, was to increase the engine displacement. Porsche decided not not to increase engine bore, but rather piston stroke. The result was the Porsche 911 2.4.
In the 1970 Porsche 911’s engine capacity was increased from 2.0 to 2.2 litres. The new 2.2-litre engine was used in all versions of the 911. With a bigger displacement, the engine produced more power and better top performance, but the torque gain also improved driveability at lower speeds.
By the mid 1950s, Ferry Porsche had decided that completely new model was needed to maintain the technological edge of the Porsche brand. The planning work of the new model started in 1957, after Ferry Porsche had defined the key specifications for successor of the Porsche 356.