The powerful and wildly complex Fuhrmann four-cam engine was initially designed and destined to be the competition motor for the mid-engined 550 Spyders, but Ernst Fuhrmann himself revealed decades later that he had taken the packaging of the engine into account to fit the Typ 547 engine in a 356 road car from early on in the design process. A cam drive utilizing spur gears or chains would have been sufficient but at the expense of the engine’s overall length, so a horizontal shaft drive between the cylinders was used to keep the engine compact. The first four-cam engines were built in just half a year in anticipation of the 1953 racing season and were capable of revving to an incredible 7,000 rpm and produced over 100 horsepower at a time when the most powerful pushrod motors were only capable of approximately 75 horsepower. After being subjected to several days of high-speed testing, it was deemed ready for competition. In its first full season of competition, it led Porsche to an in-class victory at the Mille Miglia and two class wins at Le Mans a few weeks later.
In August of 1954, the four-cam engine was fitted in a 356 for the first time using a leftover Gmünd coupe aluminum body shell and built to be an ultra-lightweight competition car. The 356 SL (Superleicht) was campaigned shortly after its completion in the most demanding rally race of its time, the Liege-Rome-Liege rally. At the conclusion of the four-day-long nonstop race, the 356 SL had taken the overall win and convinced Ferry Porsche that the Typ 547 engine was durable enough to be offered in a road car. Just two years after the Typ 547’s first test in a 550 and a year after the 356 SL’s outright victory, the 356 “GS” versions were offered to customers.
In 1957, Porsche began offering two iterations of the Carrera- the lightweight, competition-focused GT models and the GS “de Luxe”, which was by far the most luxurious Porsche constructed at the time and was aimed to satisfy the requirements of normal driving. The new type 692/2 engine increased the cylinder bore from 85 to 87.5mm to increase the total displacement to 1588cc, and the implementation of a single piece forged crankshaft facilitated the move to plain bearings to alleviate the damaged bearings and fouled spark plugs experienced by more leisurely drivers who did not treat the 547/1 competition engines as such. Additionally, the distributors were moved from the ends of the camshafts to the crankshaft, allowing for more precise ignition timing. These changes, in conjunction with an increased compression ratio, allowed for a more civilized driving experience while still producing some 100 horsepower. The de Luxe models also incorporated an Eberspacher gasoline heater at the back of the engine as standard to supplement the engine heating system, along with plush seating and additional sound deadening. Despite the additional creature comforts, there was more of an appetite for the stripped-down GT models, and as a result the Carrera de Luxe models failed to attract buyers. Total GS production for 1958 consisted of 46 Coupes, 24 Cabriolets, and 2 Speedsters while in 1959 29 Coupes, 19 Cabriolets, and 1 Convertible D were constructed.