Guide: Shelby's Stillborn Italian Stallion - a Historical & Technical Appraisal of the De Tomaso 70P
BACKGROUND
Having dabbled in a variety of motor sport disciplines since his company’s 1959 inception, Alejandro de Tomaso’s first production model, the Vallelunga Coupe, entered the final throes of development during the winter of 1964-1965.
Prior to this, De Tomaso Automobili had focused exclusively on the design, construction and racing of purpose-built competition machinery, predominantly with small displacement engines.
The firm had successfully campaigned its own Formula Junior and Formula 3 single seaters, in addition to which a handful of sports racing cars had emerged and been sold to customers. The most notable of these sports cars which was an OSCA-powered 1100cc machine that went on to score myriad victories across the Atlantic in the G Modified SCCA class.
More ambitious (and markedly less successful) had been De Tomaso’s forays into Formula 1 racing. With F1 organised to 1.5-litre regulations at the time, De Tomaso built a range of qualifying cars between 1961 and ‘63, but results had been spectacularly disappointing. In addition to OSCA and Alfa Romeo-powered machines, Alejandro de Tomaso had ambitiously commissioned his own Flat 8 engine which proved a complete disaster.
Despite De Tomaso’s lack of silverware in top flight single seater racing, the company had nevertheless captured the attention of several influential industry players as a consequence of its innovative engineering and impressive record in junior categories.
One of these companies was Shelby American with whom Alejandro de Tomaso formed a relationship during the summer of 1964 with a view to potential collaboration on a big banger sports racing car suitable for the popular Unites States Road Racing Championship (USRRC). At the time, the enormously popular USRRC was dominated by Shelby’s Cooper Monaco Type 61M (dubbed the King Cobra) and Chaparral’s 2A, which were powered by large displacement Ford and Chevrolet engines respectively.
As the Cooper platform was hardly in its first flush of youth, a cooperation agreement was signed between Shelby and De Tomaso, an unusual but not unprecedented move as Shelby had taken a broadly similar approach for the 1964 Cobra Daytona Coupe, the bodywork for which had been outsourced to Carrozzeria Gran Sport in Modena.
With an agreement rubber stamped, Shelby’s director of special projects, Peter Brock, set about designing a state-of-art body to grace a new De Tomaso chassis.
Before long, a half scale clay model had been created, the blueprints for which were sent from Shelby’s California headquarters to renowned coachbuilder, Medoardo Fantuzzi.
Unfortunately, confusion during the construction stage saw Fantuzzi wrongly convert some of Brock’s measurements from imperial to metric and, as a consequence of an incredibly cramped cockpit, the engine-less prototype that went on to appear at a press conference held at the Real Fini Hotel in Modena during January of 1965 (pictured above) was almost impossible to drive.
This embarrassing affair saw Shelby withdraw from any further collaboration, much to the irritation of Alejandro de Tomaso, who went on to name his Vallelunga replacement Mongoose (Mangusta in Italian) as this was one of the few mammals capable of killing a Cobra.
Although his main backer had pulled the plug, Alejandro de Tomaso arranged for his new sports racing car to be refined during the months that followed. An almost production-ready second car, initially dubbed the Ghia-De Tomaso 5-litri and later 70P, then went on to appear at the Turin Motor Show in November 1965. By this time, the design had been modified, most notably with a view to qualifying into the FIA’s new-for-1966 Group 6 Prototype class.
At this stage, a production run of around ten units was anticipated with a pair of these expected to form the basis of a two-car works team that would go head-to-head with the Ferrari 330 P3 and Ford GT40 Mk2.in the World Sportscar Championship.
CHASSIS
As a long-standing advocate of the central spine-type chassis, it was no surprise that Alejandro de Tomaso opted for such a layout with the 70P. What emerged was essentially a beefed-up version of the existing Vallelunga theme, something capable of handling the massive power and torque of a full fat V8 race engine.
The spine extended from the front suspension to the longitudinal mid point of the car, at which point it forked out into the rails to which the engine mounts were attached (with the engine forming a vital load-bearing structure).
At 2362mm, the wheelbase was 47mm longer than a Vallelunga.
A 113.5-litre fuel tank was installed ahead of the front bulkhead.
Suspension was via double wishbones and coil sprung tubular shocks. An anti-roll bar was installed for each axle.
Similarly, the 70P was fitted with four-wheel disc brakes.
Handsome new 15-inch diameter Campagnolo cast magnesium wheels rode on Goodyear tyres (7.4-inches wide front tyres and 12.4 at the rear).
ENGINE / TRANSMISSION
The 70P was conceived to run the latest off-the-shelf Shelby Cobra small block overhead valve 289 cubic-inch 90° V8. These engines featured a cast iron block and head, two valves per cylinder and wet-sump lubrication. They displaced 4727cc thanks to a bore and stroke of 101.8mm and 72.9mm respectively.
With a compression ratio of 10.8:1 and four Weber 48 IDM downdraught carburettors, peak output was 390bhp at 6750rpm and 341lb-ft at 4000rpm.
Ever ambitious, De Tomaso planned to improve on Shelby’s proven power unit and engines destined for the 70P were expected to come with De Tomaso’s own heads, pistons, connecting rods and manifolds which inferred the Italian firm planned to take engine capacity closer to a full five-litres or 302 cubic inches. Such a feat would have been necessary to achieve the 475bhp at 7300rpm quoted on the 70P’s debut.
In a similar fashion, rather than retain the Borg Warner T-10M four-speed manual gearbox favoured by Shelby, De Tomaso initially planned to use a five-speed unit developed in-house (along with an essential limited-slip differential).
BODYWORK
Up front, the 70P was fairly conventional: an air-piercing nose with covered headlights, an array of neat cooling solutions and the lowest profile form. There was, however, a conspicuous lack of spoilers or canards.
One of the 70P’s most dramatic features was an enormous panoramic windscreen and fully faired door windows. Conventional opening doors were installed to comply with Group 6 rules (as was a full complement of lighting and a spare wheel / tyre etc.).
Behind the open Spyder cockpit on the driver’s side, a flimsy little roll over hoop was added as a token safety gesture.
The back end of the 70P was even more dramatic than the front and where Peter Brock’s party piece could be found. Housed at the back of a single-piece rear clam with massive rear fender mounted cooling intakes was a fully integrated driver-adjustable rear spoiler.
Other unusual details around the back of the car included drag-reducing semi-enclosed rear wheels and a forward-raked tail fascia.
Fantuzzi made the 70P bodywork entirely out of aluminium which was draped over a tubular steel skeletal frame.
INTERIOR
Aside for a pair of bucket seats, the 70P was left completely un-trimmed inside. Access into the driver’s seat was over an exposed right-hand side gearbox linkage. Once inside, the panoramic cockpit canopy gave good visibility.
Satin black-painted metal was the general theme to include the basic box-type dash that housed all the essential gauges in addition to an array of warning lights and switchgear.
WEIGHT / PERFORMANCE
De Tomaso originally quoted a weight of 660kg for the 70P. However, given Ferrari’s 330 P3 Group 6 Prototype tipped the scales at 850kg, such a figure would seem unlikely.
Nevertheless, top speed would have been in the region of 180mph with a potential 0-62mph time of around four-or-so seconds.
SUBSEQUENT HISTORY AS 70P
After its debut outing at the Turin Motor Show in November 1965, the 70P was displayed the following February at the Modena Racing Car Show.
By this time, Peter Brock had quit his role at Shelby to set up his own design company: Brock Racing Enterprises. He also became the US agent for the 70P. Unfortunately though, only the one car as displayed at the Turin and Modena motor shows was ever completed and this did not remain in its original configuration for long...
CONVERSION TO SPORT 5000
During early assessment of the 70P, it was decided that some changes would need to be made to turn the original design into an effective Group 6 race car. At Fantuzzi’s workshop just down the road in Modena, the 70P’s detachable rear clamshell and doors were lifted off and the remaining body cut away in order to fit a new skin.
The second generation, more conventionally bodied car that emerged in the summer of 1966 was dubbed the Sport 5000 and did go on to race at World Championship level…
As for the original mis-calculated and engine-less prototype shown at the Real Fini Hotel in January 1965, this car later re-appeared during the early 1970s fitted with a much later aftermarket rebody and Porsche engine.
Text copyright: Supercar Nostalgia
Photo copyright: Ghia & De Tomaso Automobili - https://detomaso-automobili.com/
