FORCE FOUR GOOD

Ferry Porsche himself described the 356A Carrera Four-Cam as the perfect dual-purpose road-racer. Octane drives a prize-winning example of this competition-bred rarity

- Keith Seume

It's all about the fours: four cylinders, four valves, four camshafts, all conspiring to make Porsche's 356A Carrera the stuff of dreams. Created at the behest of Ferry Porsche himself, the Carrera's Type 547 four-cam engine represented the pinnacle of race-bred engineering when launched in 1955. It was the brainchild of Ernst Fuhrmann, who later became chairman of Porsche AG.

Fuhrmann had studied engineering at the Vienna Technical University, aptly completing a thesis on the subject of 'Camshaft drive for the control of high-speed combustion engines'. He was in at the start, joining Porsche Konstruktionen GmbH & Co KG in March 1947, then largely run by Ferry Porsche, son of founding father Ferdinand, out of a converted sawmill at Gmünd in Austria. The company's first production car - the 356 - was launched in 1948, and in 1952 he was charged with designing a new high-performance engine loosely based on the Volkswagen Beetle's air-cooled flat-four.

The target was 70bhp per litre, and Fuhrmann realised the existing VW-derived 356 engine was at the limit of its development. Its pushrod design restricted engine speeds, and cooling would be an issue in extended periods of high-speed use. He soon found an enthusiastic ally in Porsche's competition manager Huschke von Hanstein. Known as the Racing Baron, von Hanstein was all for improving Porsche's chances of victory on the track.

Capacity was set at a shade under the international 1.5-litre class limit, at 1498cc. The engine was unusual in being oversquare when long-stroke engines were still popular, allowing for larger valves and a reduction in stress on the pistons and rods at high revs, as well as typically running cooler - obvious advantages for a competition engine. The downside is a relative loss of low-end torque.