www.QV500.com - Porsche 356 A Part 3: 356 A Carrera
 
Shown alongside the single camshaft 'A' at the Frankfurt Motor Show in September 1955, Porsche’s 1500 Carrera was the most exotic 356 available. Customers could choose from a variety of configurations including the 100bhp GS in Coupe or Speedster trim and the 110bhp GT that was initially available as a Speedster only. The Carrera concept and the four-camshaft engine went back to 1952, but it wasn't until 1955 that Porsche considered their race-bred motor refined enough for public distribution.
   
The firm decided on the familiar Carrera nomenclature in homage to the epic Carrera Pan Americana road race played out at break-neck speeds over exceedingly dangerous Mexican highways during the forties and fifties. Initially reserved for Porsche’s highest performance road and race cars until the early 1970’s, thereafter the Carrera name was devalued by finding its way onto regular 911's. Using a crack four-camshaft engine (instead of the single overhead camshaft units used in the series production 356 A), the four-cam was a really trick piece of kit. With cylinder heads and barrels in light alloy, dual ignition with two spark plugs per cylinder and dry-sump lubrication, each Carrera motor was carefully built by hand, taking over two weeks to complete plus a further couple of days to tune. Hirth roller bearing crankshafts further differentiated Carrera's from the single camshaft cars.
 
Designated Typ 547, displacement was 1498cc with a bore and stroke of 85 x 66mm respectively. Type 547's were available in two states of tune; GS and GT. In GS trim, output was 100bhp at 6200rpm whilst GT's boasted an extraordinary 110bhp at 6400rpm, this thanks to attention to the camshafts and ignition. Otherwise, both engines were broadly similar with compression at 9.0:1, two Solex 40 PII 4 twin choke carbs and identical Typ 547/1 designations. Performance figures were extremely impressive, these little gems having been able to fly along at in excess of 120mph, 0-60 taking less than 10 seconds.
   

Carrera's were available with either T-1 Coupe or Speedster bodywork, lightweight aluminium panels being used for the doors, bonnet and engine cover. The only external details unique to these cars were dual outlet exhaust pipes exiting from underneath the rear bumper and anodised gold Carrera scripting on the engine cover and front wings. Wider wheels filled the arches more, Carrera's having also been available with desirable Rudge knock-offs. Inside, the heater and radio were junked, hardwearing cloth and vinyl being used throughout (save for leather seats). Interestingly, the dash featured two additional switches for regulating the ignition current to the coils and spark plugs. Debuted alongside the pushrod 356 A at the Frankfurt Motor Show in September 1955, the four-cams were known as the 1500 GS Deluxe Carrera and 1500 GT Carrera. Both received a favourable reception from all who saw them.
 
By May 1957 a more extreme and substantially lighter GT became available and was this time offered in both Coupe and Speedster configurations. A much more serious proposition for the track, there were front brakes sourced from the 550 and 1500 RS Spyder’s whilst bigger twin-choke Weber 40 DCM downdraught carburettors could also be specified. Outside, flimsy lightweight bumpers were joined by Perspex instead of glass (save for the windscreen), cockpits being equipped with aluminium bucket seats and leather window retaining straps (instead of traditional winders).
   
Additional weight was saved by junking the rear seats whilst other noteworthy additions were a Nardi wood-rimmed steering wheel and 21-gallon fuel tank. Then, during September 1957, the T-2 body was phased in. Besides the obvious addition of Carrera scripting, the only major difference between these road racers and single cam examples was the lack of exhaust pipes exiting through the rear bumper guards as seen on the production T-2. From May 1958, Carrera's were fitted with Typ 692 1600cc engines featuring the more reliable (if a little less exotic) plain bearing crankshaft. Displacement was increased to 1587cc thanks to a 2.5mm bore increase (87.5mm up from 85mm), stroke remaining unchanged at 66mm. Two distributors were driven from the front of the crank and a pair of oil coolers mounted behind the front horn grilles and incorporated into the dry sump system.
 
Like before, two versions were available, the GS with a Typ 692/2 engine (105bhp at 6500rpm) or the GT with its Typ 692/3 motor (115bhp at 6500rpm). The GS engine was normally fitted into Deluxe models and ran a 9.0:1 compression ratio and two Solex 40 PII-4 twin choke carbs. By contrast the competition-spec GT motor, the Type 692/3, had compression set higher at 9.8:1. This engine commonly ran with two Weber 40 DCM 3 twin choke carburettors and also featured sodium filled exhaust valves. Performance figures were once again moved on and production continued until the 356 B arrived in September of 1959.