The last twelve months have been surprisingly healthy for the classic car market. Despite the adverse economic environment and the restrictions on travel, not to mention the difficulties in physically inspecting or testing anything, plenty of cars have found a way of changing hands. In the UK as lockdown restrictions start to lift and retail premises open up, it is clear that an increasing number of buyers are chasing a shrinking amount of stock.
Within the Porsche world, there has been a lot of buzz around more modern classics such as the 964 RS, 997 GT3 and Carrera GT. Less obvious perhaps has been a resurgence of interest in Porsche’s meisterwerk, the 1973 2.7 Carrera RS. We have recently witnessed several of the best examples discreetly changing hands for values last seen in the boom years of 2015 / 16 and while early 911s in general are solid they have not yet made it back to the market peak. That means that an RS Touring is now three times the value of an equivalent 2.4S from the same year. It is undeniably a great car but that is now a very sizeable premium to the rest of Porsche’s contemporary catalogue. Is the 2.7 RS really that special?
In answering this question, the comparison with the 2.4S is an interesting one to make. The 2.7 RS has the reputation of being a light weight, exotic, competition focused one-off. As the legend goes, it was created purely to act as the basis for a racing car and not with any commercial motivation in mind. That makes it sound radically different from the car that went before it, but was it?
In 1972 the 911 was already a highly successful car in motor sport but with the competition hotting up Porsche needed to stay ahead of the game. The FIA Group 4 rules that governed top tier GT racing at the time allowed engines to be bored out but only to the capacity limit of the car’s class. That meant the 1972 2.4S could be bored out to the 2.5 litre class limit but no further. The first thing Porsche needed for their 1973 model line-up was a 911 with an engine bigger than 2.5 litres.
As a result, the most significant change that was made to the range topping car was to increase the engine bore from 84mm to 90mm. This was not a trivial task to perform on an engine originally conceived as a 2.0 litre and required the adoption of a new coating technology for the cylinder linings. The result was a 15% increase in capacity but otherwise the engine was mechanically virtually identical to the 2.4, including the compression ratio, valve sizes and cam timing.
The other pressing racing priority was to improve the car’s road-holding and it had become obvious that the secret with the rear-engined 911 was to put much wider tyres on the back than the front. Again, the GT rules allowed the use of wider wheels but only as long as they remained covered by the wheel arches, which themselves could only be extended by a certain degree. Therefore, the second thing the new road car needed was widened rear wheel arches.
Accordingly, Porsche re-shaped the rear wings which allowed the use of wider 7” back wheels and a slightly increased track. The anti-roll bars were also stiffened however that was as far as changes to the running gear went and the suspension and brakes remained largely unaltered. Porsche did take some measures to lighten the car by using thin gauge metal panels and lightweight glass however their importance can be overstated as they probably saved less than 20kg overall.
These rather modest sounding upgrades gave Porsche the needed room for manoeuvre and enabled them to produce a racing version of the 911 for 1973 that was significantly quicker than the previous season’s car. So much so that the RSR, as it became known, won several of the endurance racing classics outright that year, including the Daytona 24 Hours and the Targa Florio. These racing successes certainly added more cachet to the 2.7 RS than had been the case with earlier 911s.
This leads me to another major difference between the 2.7 RS and 2.4 S which is how the car was sold.
Ever since Porsche started homologating the 911 for racing it had been creative with the way it defined the standard specification of the road car in order to have it recorded at the minimum possible weight. This was important because the racing versions were not allowed to weigh less than this official figure. The trick they had used before was to bring a car to market with the most basic specification possible (known as Grundtyp in German) and then offer customers an option package which converted it into a practical road-going proposition for a nominal cost. For the preceding 911S this was done in such a way that the customer had to opt out of the upgrade and consequently almost all cars were delivered fully trimmed.
However, the FIA had started to wise up to this chicanery and Porsche decided that for 1973 a more overt offering of the basic car would be prudent. They decided to sell the car to the public in an aggressively stripped out form with even the anti-roll bars removed. These cars have subsequently become known as RSH or “RS Homologation” and were listed at 960 kg wet. It was something of a pretence, but every one of the first 500 2.7 RS were first completed as an RSH and driven to the Stuttgart weighbridge to be officially recorded. Of course, Porsche anticipated that almost nobody would actually want their 2.7 RS delivered in such a Spartan form, so customers were given the choice of two option packages.