The Porsche 904 GTS was the genesis for the successful Porsche competition participation from the 1960's to the 1970's. The car's mid-engined layout was clothed with a lightweight glass fibre body bonded to the steel chassis and was the handiwork of "Butzi" Porsche. The first Porsche to use a ladder chassis and fibreglass body, the bodywork was built by Heinkel due to their GRP manufacturing expertise and the double wishbone suspension reflected Porsche's contemporary F1 experience. Typically a 4 cylinder 4 cam engined 904 would weigh in at a modest 655 kgs. The beautiful aerodynamic shape produced a low drag co-efficient of 0.34 with a resulting top speed depending on gearing of around 160 mph. The car was extremely successful in group 3 GT racing and also won a number of events outright against much larger engined opposition including the Targa Florio and the Monte Carlo rally.
Purely built as a competition vehicle, nevertheless the car could be used on the road and 108 examples were built to satisfy prevailing Group 3 regulations of the time. A few more cars were later built from spare parts at the factory.
This model was perhaps the last realistic dual purpose road usable GT racecar and also in no small part due to the beauty of the 904 body shape, today are highly coveted. The majority of cars were built with the 4 cam Porsche engine in varying states of tune, with power outputs ranging from 155 bhp for road use, to 180 bhp with a full race exhaust. The new Porsche 6 cylinder engine was not quite ready when the car was launched, but the chassis was designed to accommodate the flat six and even the flat eight F1 engine in 2 litre guise. Although the 4 cam engine was installed in the bulk of 904 production, the complex nature of the engine and it's attendant servicing demands meant that many cars were subsequently changed to the ultimately more ubiquitous flat six which also offered a useful power upgrade.
As a purebred competition car, albeit with genuine road going potential, the cars in period were frequently fitted with different engines, gearboxes and the fragile nature of the chassis and bodies, meant there are few genuinely original well documented "survivors" with active competition history. Many of the surviving cars have "chequered" histories and although often built to high standards are obviously not original in the strictest sense of the word.
The rarity and exotic nature of the 904 model mean that even though they present as fabulous dual purpose road and racing cars, many have long since been retired into major collections. Many of the cars that are racing today, have varying degrees of originality, but even in this state are still highly desirable.
If you are considering racing a 904 today and harbour any hopes of being successful in the highly competitive environment of historic racing today, you are typically faced with the dilemma of whether you preserve the original engine and gearbox in a crate - if it still exists with the car(!) or whether you fit a newly built fresh engine to modern machining tolerances. The wisdom of using or even the likelihood, that a 904 has it's original lightweight chassis today, is doubtful....
So this brings the question to the fore that if you wish to experience the exquisite 904 driving experience, do you risk running aged original components - if they even exist on your car - or do you replace many of the components with modern items with attendant improvements in safety and performance?
For us, these cars are all about driving them and experiencing them in the environment for which they were conceived. Here at Historika we have a particular soft spot for the 904 as we have spent the last 3 years rebuilding our own genuine factory built car with a view to completion in the Summer of 2021.
The lengths we have gone to ensure that our own original car has been rebuilt to exacting factory specifications have been exhausting. We have invested a great deal in the remanufacture of parts that have been obsolete for many years and reverse engineered all components so that when we get behind the wheel of our car on track later this year, hopefully all the hard work will be amply rewarded and we can drive the car in a manner which was intended!
Naturally our 40 years of expertise with Porsche competition flat six engines will be applied to the power plant of our own 904, although today, early 4 cam engine options are now also an option, due to significant tooling investment.
This "labour of love" has been the product of significant expenditure and tooling and we are looking to capitalise on our hard won 904 expertise by offering a highly limited production run of cars built to FIA Appendix K specification for racing. The cars will be built without compromise and will present new owners with an opportunity to buy a turn key racecar which can also be used on the road, at a price which compares favourably to the handful of 904's which are periodically available on the market today, many of which bearing "interesting" histories which make them very difficult to value!
Historika 904 Prototype
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