The Bizzarrini 5300 GT was a sports car series produced in small numbers by the Italian car manufacturer, Automobili Bizzarrini. The car is closely related to the Iso Grifo, by the Milan sports car manufacturer Iso Rivolta. The car was designed as a racing version of the Grifo and was initially marketed under the name Iso A3 / C. After business deals between Bizzarrini and Iso Rivolta came to a close, it was introduced to the automobile market in 1965 as an independent model. The Bizzarrini 5300 GT had two distinctly different models, one being more of a Type-R version. However, the volume of production of both versions underperformed expectations. In addition, the 5300 GT did not succeed in the motorsports industry as well as the Iso A3 / C did between 1964 and 1965.
Iso Grifo Giotto Bizzarrini, the owner of the Tuscan company Automobili Bizzarrini at the time, had been commissioned in 1962 to design the chassis for the Iso Rivolta 300. A year later, he also designed the chassis for Bizzarrini Iso's second model, which was a sporty two-seater in the same geist as the popular grand tourer. The aforementioned vehicle would have the same 300-bhp engine of the Corvette with Giorgetto Giugiaro's engine chassis design similar to those made by the Bertone company. It was initially named the Iso A3 / L, the L meaning Lusso (italian: luxury) and meant that it was to be a comfortable on-road vehicle despite having such powerful specifications. This model became known later as the Iso Grifo.
Sports version of the Grifo
Long before the 1965 production of Iso Grifo, Giotto Bizzarrini adapted the A3 / L for use in races. The idea for this project came from Bizzarrini: He believed that sales of the road sports car A3 / L could be significantly improved by its success in the racing industry. Renzo Rivolta supported the idea, although he was skeptical about car racing.
The result of Bizzarrini's work was the Iso A3 / C (for Competizione). The A3 / C had an independent body had but had the similar in terms of suspension compared to the A3 / L. This was also true for the engine: Both models were fitted with a 5.3-liter eight-cylinder engine used in the Chevrolet Corvette. The public saw the (then still-unpainted) Car Debuts in the Turin Motor Show in October 1963. It was exhibited on the stand of Iso Rivolta, while the street version, the A3 / L "Grifo", was displayed on the Bertone stand.
Six months later, the A3 / L made its first appearance in a racing event: Automobili Bizzarrini entered the 12-hour race at Sebring with two Iso cars with the help of the company Iso Rivolta. Unfortunately, both vehicles had technical defects. In the following two years, there were more racing appearances, including the 24-hour race at Le Mans, being partly successful.
From 1965, the A3 / C was sold at a small scale in Livorno. Yet, Bizzarrini's sales were still outdone by Iso Rivolta there.
Separation of Iso Rivolta
In 1965, tension built between Renzo Rivolta and Giotto Bizzarrini. Bizzarrini had fitted some car stocks of the A3/C model with its own brand logo instead of Iso Rivolta's. Of greater weightage, however, was the fact that Bizzarrini had already registered the name "Grifo" as a trademark.
Rivolta and Bizzarrini agreed to settle the dispute by breakdown of market segments: Iso Rivolta was given the brand name Grifo for exclusive use and was limited to only producing the on-road A3 / L model under the name Iso Grifo, while Giotto Bizzarrini would produce the sports version of A3 / C starting from the late summer of 1965 under its own name as the Bizzarrini GT 5300. Iso Rivolta also received suspension and transmission parts from Bizzarrini, which were actually insufficient to build 50 more vehicles.
In the second half of 1965, Bizzarrini presented a line of vehicles that were based on the designs for Iso Rivolta A3 / C, in Livorno once again. Different versions were produced according to specifications:
- The on-road version was titled the Bizzarrini 5300 GT Strada.
- A racing version was called the Bizzarrini GT Corsa 5300, factory-produced for endurance racing. Some of these vehicles within this model were custom-fitted with Strada elements found on the Corsa, by customer specifications.
- The Bizzarrini Spyder model was also produced, but was limited to 3 copies.
Current production and market situation
After Renzo Rivolta left, Bizzarrini produced 20 to 30 cars of the A3/C model for Iso. The details were inconsistent; it could have been 22 cars (as verbally announced), or 30. It is, however, confirmed that a 1965-produced copy was fitted with a plastic body.
The number of copies of the Bizzarrini 5300 GT produced by Iso is also very unclear. The data in literature and other sources vary widely. Until the 1990s, it was largely assumed that a total of 149 copies of the GT-5300-series were produced. In recent literature, this number is now seen as far too high. Meanwhile, most sources cited about 100 to 110 completed vehicles. Others still believe that between 1964 to 1966, only 78 vehicles were produced and only a few more were built between 1967 and 1968 due to a shifting of focus to the successor model, the Bizzarrini P538. In most cases, it is unclear whether this data referred to the number of built Iso A3 / C cars or just those manufactured by Bizzarrini. There is an agreement that the Corsa versions are much rarer than the Strada models. Most sources estimate a maximum of 10 copies of the Corsa version of the GT5300.
Giotto Bizzarrini himself could not clarify the exact number of cars produced. He claims that there was no exact accounting of the cars, since he had only taken care of the technical side of the business. In addition, no consistent chassis numbers were used.
Today, the Bizzarrini 5300 GT, both the Strada and Corsa versions are sought classics, fetching high prices among collectors. A 5300 GT Strada in good but not excellent condition was estimated in 2010 to cost approximately EUR 250,000, and could fetch even higher prices at auctions. In January 2011, the auction house Coys of Kensington auctioned one of the last GT Strada 5300 cars in London for almost 280,000 euros. RM Auctions did the same just four months later in the Concorso D'Eleganza Villa d'Este auction in Cernobbio; a very similar car made sales proceeds of €400,000.
The Bizzarrini 5300 GT is based, like the almost identical Iso A3 / C, on a semi-monocoque made from welded aluminium sheets. Structurally it was similar to that of the Iso Grifo A3 / L, however the wheelbase was shortened by 50mm. The rear suspension was also similar to the Grifo A3 / L, but the front suspension was original.
A special feature of the 5300 GT was the location of its engine: In an effort to center the weight optimally, Bizzarrini placed the heavy American engine behind the front axle. This meant that parts of the engine - including the distributor - were found quite near the passenger; in fact, the dashboard had a trap door (sort of a flap) in which the distributor was located.
The 140 liter tank was also moved to optimise weight centering: One tank was located in the side sills beneath the doors on both sides, and a third, larger tank was installed behind the seats. This gave the Bizzarrini a weight distribution in the ratio of 52 to 48.
In all models, Bizzarrini used a regular 5.3-liter eight-cylinder type high-performance Chevrolet Corvette 340. Bizzarrini offered this engine in various processing and power levels. The regular tuning measures for all engines were revised intake and exhaust ports, and a modified crankshaft. For each model, however, different gasifier systems were used. In most Strada-type cars a Carter, later Holley quad carburetor was used, while the Corsa models used a dual carburetor by Eduardo Weber (Type 42, Type 45 DCOE later). The Strada version had a 365-horsepower engine, while the Corsa models had an engine capacity of about 400 to 405 horsepower, although other sources suggest 420 hp.
At least one Bizzarrini GT car was designed for racing with a 7.0-liter eight-cylinder engine by Ford with a power output of 450 hp, or 550 hp according to other sources. This vehicle was later given bodywork by Neri e Bonacini, sold as the Nembo 7 Litri.
The body of the GT 5300 was similar to that of the Iso A3 / C. She had almost no resemblance to the Iso Grifo A3 / L, being closer to the design of a gran tourer. Because of this, the design of the sports car body is usually attributed to Giorgio Giugiaro and Bertone. Some sources, however, claim Giugiaro's influence on the design of the vehicle, saying Giotto Bizzarrini had designed the body along with Piero Vanni while Giugiaro and Bertone had only made a few refinements.
The body was designed for sportcar performance. The Strada had a height of 1.11 meters, yet the Sport model Corsa outperformed this at only 1.06 meters. The headlights were set back with a Plexiglas cover, whereas the windshield was arched. Car bumpers were completely absent; some Strada models had "fake" bumpers caused by optical illusions. The body was aerodynamically efficient and its drag coefficient was no more than 0.30.
Under Bizzarrini, Piero Drogo made the A3/C model for Iso Rivolta in the Carrozzeria Sports Cars in Modena. After Bizzarrini and Rivolta had separated, Drogo's relationship with the company was also severed. The aluminum bodies for the GT-5300 models were replaced at the small Modenese-made Karosseriewerk BBM in September 1965.
Bizzarrini 5300 GT Strada
The GT Strada 5300 was the most widely used version of the Bizzarrini. She had an aluminum body, was usually equipped with the 365 hp engine and offered a bit of comfort upgrades in the interior. These included side crank windows, a vent made by the company Fiat, along with a related with leather dashboard, which was panelled with wood in some cases.
Some models intended for the U.S. market were called GT America. They were similar to the European Strada.
Bizzarrini 5300 GT Corsa
The 5300 GT Corsa was designed for racing operations modification of the Strada, which was obviously sport-oriented. Bizzarrini reduced vehicle weight by 40 kilograms, by removing the aforementioned comfort upgrades. These included the inner door panels, wind-up windows - they were replaced by opening windows - and the ventilation. A thinner body (and thus lighter aluminum plating) was fitted for this model. The Corsa models have additional ventilation holes in the rear window. In at least four cars, the body was made of plastic.
Bizzarrini 5300 Spyder SI
The Bizzarrini Spyder models were completely different from the 5300. Only three copies were made: One prototype and two distinctly different vehicles which were sold.
- The prototype of the Spyder was developed in the second half of 1965 and was revealed to the public at the Geneva Motor Show in March 1966. The basic line of the vehicle was similar to that of the 5300 GT Strada, but had a removable roll-bar, as well as removable roof parts. The chassis of the exhibition copy was not given enough focus, and so the car had a high level of twist torsion. Giotto Bizzarrini described the build as "unstable" but this was not rectified, not even when the roll bar was fixed in later. The Spyder prototype was not for sale. After some time, after the bankruptcy of Automobili Bizzarrini, Bizzarrini made a similar car at the request of those who bought over the company. However, it collapsed after only 2000 miles due to high torsion suffered on the windshield. Nothing was heard of the prototype for nearly 30 years after, until a collector bought it and fitted it with a body in the older "standard" Spyder style.
- After the failure of the Spyder prototype, Bizzarrini designed another version of the 5300, which had a firmly welded roll cage and some reinforcements in the area of the windshield. The panels were manufactured at the company Stile Italia. Now dubbed the Spyder SI (for styles Italia), two copies were made in 1967 and 1968. The first vehicle, painted red, was manufactured for Bizzarrini's investor Harold Sarko; the second, blue-painted one was for Virgilio D'Iselio, the owner of Stile Italia. No more additional cars of the model were manufactured. The series was discontinued due to lack of funding.
Commitment to motor racing
The Bizzarrini GT 5300 was designed just like its predecessor Iso A3 / C for participation in racing events. Giotto Bizzarrini used the A3 / C in 1964 and 1965 for Iso Rivolta at various long distance races and has achieved some success, including in two years class victories in the 24-hour race at Le Mans.
Even after Bizzarrini and Renzo Rivolta had separated in the summer of 1965, he continued working at the motorsports factory. Bizzarrini worked on a new vehicle, which was given the chassis number BA4 106 and should have been used in all races in the season of 1966. However, the production brought no success. At its first entry, in the 1000-kilometer race at Monza, Bizzarrini's drivers, Edgar Berney suffered defeat. Antonio Nieri had the same fate due to technical failure at the prestigious Targa Florio in May 1966. Bizzarrini did not participate in the 1000-kilometer race at Spa-Francorchamps and the Nürburgring due to funds being focused to participate in the 24-hour race at Le Mans in June 1966. Here Bizzarrini first appeared with his new design, the P 538. In addition to that, Bizzarrini introduced prototypes for the 5300GT under the drivers Sam Posey and Massimo Natili. They were positioned four spaces in front of the P538. Still, the event was not successful for Bizzarrini. Posey and Natali were disqualified because they had run over a security line in the pit lane.
In 1967, Bizzarrini 5300 GT was fitted with a seven-liter eight-cylinder engine from Ford. The car was used by Edgar Berney and Jean de Mortemart in the 1000-kilometer race at Monza, but did not finish. An explanation offered for the 24-hour race at Le Mans 1967 was not accepted because the sponsors thought it improper. Thus, Giotto Bizzarrini's involvement in motor sports came to an end.