In reality, this was more a question of keeping the matter as low profile as possible. Although almost 40 years have elapsed, Rolf Sprenger still recalls the 3.1: “We had to do something for buyers who were disappointed that their 911 SC had ten per cent less power than the Carrera 3.0. You didn’t expect that from Porsche and we wanted to offer customers a factory option rather than sending them to the tuners. I no longer have any paperwork, but I believe that over a year and a half we did 200 to 300 of these upgrades.”
Almost all of these would have gone in the first instance to German customers. Former works driver and Motorsport manager Jürgen Barth is the acknowledged expert on the Porsche model range and racing history. His Das Grosse Buch Der Porsche-Typen is the benchmark reference. He, too, recalls the 3.1 as well as he might because at the time he was undertaking what was then entirely unofficial competition development of the 3.0-litre engine: this would enjoy further success, winning the Tour de Corse in 1980 among others before its ultimate expression in the superbly focused SC RS.
“Yes I remember the 3.1, but I can’t confirm how many were made: there aren’t any figures as it was built in the Reparaturwerkstatt not the factory,” Barth recalls. The Reparaturwerkstatt produced the 3.1 through 1979 and 1980. When the model year 1981 SC was announced with 204hp, the 6bhp advantage offered by the 3.1 was felt insignificant and the SC-L upgrade option was quietly dropped. Sprenger feels it was only a limited success: “
At DM 7,500, it was expensive (a 911 SC cost DM 39,900 when new) and you were still responsible for paying for TV approval.” Meanwhile the Moritz and Ruf conversions were available for DM 6,000 each. As for these two aftermarket tuners, Alois Ruf did comparatively well with his SC-R, selling over 400: this was the Ruf-Porsche 911 that established his credentials before he turned to the turbos. Using 98mm bore with a 70.4mm stroke, making a swept volume of 3,185cc, together with a slightly higher (9.8:1) compression ratio and polished cams, his 217hp 911 would later offer similar performance to the heavier Carrera 3.2. Prolific Porsche racer and tuner Max Moritz’s version was also 3,185cc, but he reputedly sold only about 100 cars.
So what of such a car today? The blue SC-L in our pictures belongs to Belgian enthusiast Cengiz Tekin, who has owned numerous air-cooled Porsche 911s long before they went out of production. “I have a 3.0-litre Carrera Targa, which I’ve just driven 2,000km on the Tour Amical from Venice to St Tropez, and the main difference I feel with the SC-L is the torque: subjectively, both cars are about the same in acceleration but with the SC-L you feel the pick up earlier from about 2,800rpm, while with the 3.0 you wait until 3,300rpm for the same effect. The 3.0-litre Targa warms up more quickly than the SC-L with its larger oil cooler.”
The sound as the 3.1 fires could be any SC or 3.2, that same eager, growling idle slightly lower pitched and less raucous than earlier mechanically injected and carburetted 911 engines. Once on the move, that increase in torque and readiness to pull from quite low rpm is noticeable and the SC-L is very like the 3.2 in this respect. But this is a 1970s car: its documents show a weight of 1,160kg, a good 100kg less than the later G50 3.2 cars, and the SC-L feels light and more agile, the unassisted steering easier than the 3.2’s system. Combined with the (then new to the 911) servo brakes and with a 915 gearbox in good fettle, this is a surprisingly pleasant 911 to conduct at town speeds.