As the road-legal 906 replaced its 1964 predecessor – the 904 – Porsche initiated a new era of under 2.0-liter GT racing. But why? The 904 had always given Porsche dominance in the sub-2.0-liter GT class, and it still had plenty of potential for further improvements. 

Well, there were a couple coalescing factors that caused Porsche to switch gears, and it turns out that the German marque was on the right side of history – again.

Time for a new design

The first reason was Ferrari’s V-6 Dino, an incredibly fast car for its class that was about to smash Porsche’s dominance. Then came the fact that reparation of the Carrera 904’s body was a real nuisance, because the timeworn bonding technique caused the rigidity of each chassis to vary widely. This caused the aspiration to switch the design back to a body based on tubular space frame technology.

Finally, in 1966 the homologation rules for the GT class were changed with the production unit demand being decreased from 100 to only 50 examples. This was a number that the marketers of Porsche felt they could sell in any form – however “un-road-like” their racecar was looking, meaning that the box section frame was no longer a necessary compromise.

Porsche’s young blood

However, the most important factor was Ferdinand Piëch – the grandson of Dr. Porsche who got the honor to head Porsche’s racecar R&D department at age 28. Naturally, the young blood wasn’t going to roll with the concept of his predecessors, for his fresh eyes were torn by all the factors mentioned above and more.

The biggest change came from moving the design process to the wind tunnel, which resulted in the sleek design that characterized the 906. While not everyone may appreciate this new design style, with a c/d of .35 it was certainly far more aerodynamic than it’s forerunner! 

The 906 on the track 

While the 906’s flat-6 engine was originally developed for the 904, a victory in the 2-liter prototype class and 6th place overall at Daytona 1966 proved that the engine was a perfect match for Porsche’s new Carrera. Yet, the Carrera 6’s most important race came 7 weeks later, because that’s when it first faced-off with Ferrari’s new Dino at Sebring ’66.

After 12 hours of racing the Sebring track, it was Porsche’s 906 that got the victory over the Ferrari Dino. As such, Porsche set an important precedent: it was toughness rather than speed that was the deciding factor in the many endurance races to come. Accordingly, many of the racing Porsches that followed were powered by the same flat-6 that gave the 906 its early success!