Guide: Gunning for Ferrari - a Historical & Technical Appraisal of the Shelby Cobra Daytona
Background
Since 1962, various iterations of the AC and Shelby Cobra had been used to win myriad races and championships. However, the one title that had proven elusive was the World Sportscar Championship.
In 1962, the FIA had switched the World Championship to focus on production-based Group 3 GT cars. Traditional Sports Prototypes were still eligible to run a limited number of events, but points scored by these more highly developed cars would go towards a separate Coupe des Sports.
By contrast, the prestigious World Manufacturers’ Championship was decided by Grand Touring machinery.
The all-important over-two-litre World Championship was won by Ferrari in 1962 and 1963 despite the 250 GTO used by Scuderia Ferrari and their customers having been in clear breach of the rules.
The FIA’s Group 3 regulations for Grand Touring cars stipulated 100 production vehicles had to be built within a twelve month period to qualify. Special coachwork was permitted for racing variants of the homologated model, but the mechanicals could not be modified. The FIA also permitted chassis strengthening, but not chassis weight reduction.
As the 250 GTO used a custom small diameter tubular frame, it should have been thrown out unless 100 had been built.
They weren’t.
However, such was Enzo Ferrari’s influence that the FIA ultimately allowed the GTO to race. Unsurprisingly, it went on to dominate in 1962 and 1963.
Ferrari tried to go a step further for 1964 when the firm attempted to homologate the mid-engined 250 LM, but this time the application was unequivocally rejected. Instead, the compan had to develop a hastily rebodied low drag Series 2 GTO for the 1964 season.
Meanwhile, over in the USA, Carroll Shelby had started work on a special-bodied Cobra to take the fight to Ferrari.
Based on the existing Cobra chassis and drivetrain as per the regulations, the Cobra Daytona addressed the Cobra’s biggest weakness: aerodynamic drag.
In an attmpt to address this issue, FIA-spec. Cobras had used special hardtops over the years, but none lowered resistance sufficiently to keep up with the likes of Ferrari and Jaguar on high speed circuits. At Le Mans, Cobras were typically limited to just over 150mph, while the Ferrari 250 GTO topped out at nearer 180mph.
Shelby asked Peter Brock to design the Cobra Daytona’s aerodynamic new body and had Bob Negstad optimise the suspension. Shelby’s official test driver, Ken Miles, was also deeply involved having worked on the Cobra project from the beginning.
The first Cobra Daytona, chassis CSX2287, was completed in October 1963, after which Shelby embarked on an intensive test programme with much work carried out at the nearby Riverside circuit.
The new car had been christened Daytona as it would debut at the Floridian circuit in the opening World Sportscar Championship race of 1964.
Chassis
Each Cobra Daytona was built around a reinforced version of AC’s original tubular steel Cobra chassis. Ken Miles altered the driving position to suit the new low-line body, but the 2286mm wheelbase was retained.
Four wheel independent suspension was via lower wishbones, an upper transverse leaf spring and adjustable Koni shock absorbers. Anti-roll bars were installed at either end along with Girling disc brakes.
15-inch magnesium alloy centre-lock rims measured 6-inches wide at the front, 8-inches wide at the rear and were originally shod with Goodyear tyres.
Track dimensions were identical to the 1964 FIA spec. Cobra.
Engine / Transmission
The engine and transmission were also imported from the latest Cobra which meant a 289 cubic-inch Ford 90° V8 under the hood.
Front longitudinally mounted, the engine featured a cast iron block and head, two valves per cylinder and wet-sump lubrication.
Displacement was 4727cc thanks to a bore and stroke of 101.8mm and 72.9mm respectively.
The compression ratio was 10.8:1 and four Weber 48 IDM downdraught carburettors were installed.
Although technically inferior to some of the all-alloy, dual overhead camshaft, dry-sumped motors used by the Europeans, Ford’s small block overhead valve V8 typically developed far more horsepower than its rivals.
Peak output was 390bhp at 6750rpm and 341lb-ft at 4000rpm which compared favourably to anything Ferrari had to offer.
Transmission was courtesy of a Borg Warner T-10M four-speed manual gearbox, a single dry-plate clutch and limited-slip differential.
Bodywork
Despite the Cobra Daytona’s aerodynamic profile, Peter Brock’s design was styled without access to a wind tunnel.
The new lightweight aluminium shell bore little resemblance to the base car, but looked like a winner from the off.
At the front it featured a streamlined nose with covered headlights. Inset spot lights were positioned either side of a primary intake that was much smaller than the standard Cobra.
A large radiator cooling vent was cut from the bonnet along with supplementary slots behind each front wheel. Various scoops were subsequently added around the front scuttle area.
The sloping fastback roof culminated in a Kamm tail to which an upright spoiler was later grafted in place.
Two side exiting exhaust pipes were located down each sill.
Brock and his team created a wooden body buck from which the aluminium panels for the first car were formed. The panels were fabricated by California Metal Shaping in Los Angeles. Assembly then took place at Shelby’s workshop in Venice, California.
Once the prototype was complete, production of five subsequent bodies was outsourced to Carrozzeria Gransport in Modena, Italy. The wooden buck was sent across the Atlantic where several changes were made to the windscreen and roof. These alterations were for cosmetic reasons, but resulted in a slightly lower top speed.
Compared to the standard FIA Cobra, the Daytona variant was 310mm longer, 180mm wider and 60mm lower.
Interior
Cobra Daytona cockpits were just about as basic as they could be.
A rudimentary black metal dash housed a variety of instrumentation while the central control panel was home to myriad flick switches and warning lights.
Bucket seats were trimmed in black vinyl while everything else was left in bare metal.
Most of the rear quarters were taken up by the covered fuel tank and spare wheel.
Weight / Performance
The Cobra Daytona weighed in at around 1040kg compared to 1020kg for a standard-bodied FIA-spec. 1964 Cobra.
Depending on gear ratios a top speed of up to 188mph was possible (up from around 150mph) while 0-62mph was identical at 4.1 seconds.
Production
Following completion of the prototype in October 1963 (CSX2287), a further two Cobra Daytonas were assembled for the 1964 season: CSX2299 and CSX2300.
Another car, CSX2286, was also partially assembled on a unique a long wheelbase chassis in order to run a big block motor at the ‘64 Le Mans, however, the project never got beyond 70% completion after Ford pulled the plug on the idea.
CSX2286 did eventually see service during the 1965 season, by which time it had been reconfigured with a standard wheelbase chassis and 4.7-litre engine.
The 1965 season also saw a further pair of Cobra Daytonas emerge, CSX2601 and CSX2602, which took the total number of cars to six.
Competition History
The 1964 season saw an epic battle between Shelby and Ferrari.
Shelby took Division 3 GT class honours at the Sebring 12 Hours, Le Mans 24 Hours, Goodwood Tourist Trophy and Bridgehampton 500km along with two hillclimbs: Freiburg-Schauinsland and Sierre-Montagna-Crans.
Meanwhile, Ferrari emerged victorious at the Daytona 2000km, Targa Florio, Spa 500km, Nurburgring 1000km, Reims 12 Hours and Tour de France. The Italian manufacturer also won two hillclimbs: Consuma and Rossfeld.
As only a manufacturer’s best six race results plus one hillclimb counted towards their final points tally, Ferrari ended up with 84.6 points compared to Shelby’s 78.3.
However, it was a different story in 1965 as the car Ferrari created to challenge the Cobra Daytona (the 275 GTB Competizione) was not approved for the Grand Touring class owing to a breach of regulations. Unlike 1964 (when the Series 2 GTO had been hastily prepared once the 250 LM’s GT class application had been thrown out), on this occasion Ferrari refused to have a new challenger made up and there was now nothing in the way of factory GTO support.
As a consequence, Shelby was expected to walk the 1965 series.
In terms of victories, the American outfit comprehensively outscored Ferrari that season with Division 3 GT class wins at the Daytona 2000km, Sebring 12 Hours, Monza 1000km, Oulton Park Tourist Trophy, Nurburgring 1000km, Reims 12 Hours, Coppa Citta di Enna and Bridgehampton 500km along with the Rossfeld Hillclimb.
However, Ferrari came out on top at the Targa Florio, Spa 500km, Mugello GP and the Le Mans 24 Hours (where the organisers permitted the 275 GTB Competizione to run in the Grand Touring class and it finished third overall),
Accordingly, with dropped scores, the championship was much closer than it otherwise might have been: Shelby ended the season on 90 points compared to Ferrari’s 71.3.
A surprise end to the ‘65 season saw Shelby unexpectedly head to the Bonneville Salt Flats in Utah at the request of tyre partner Goodyear. Here, the Cobra Daytona set 23 National and International FIA speed records to include a 1931 mile run around Bonneville’s twelve mile loop during which Craig Breedlove and Bobby Tatroe averaged 150mph.
Text copyright: Supercar Nostalgia
Photo copyright: Ford - https://www.ford.com, Dave Friedman / The Henry Ford - https://www.thehenryford.org/
