Iso Grifo A3C and Bizzarini 5300 GT 1963-1968

Giotto Bizzarini was graduated engineer at the University of Pisa in 1953. He worked a few years for Alfa Romeo before joining Ferrari. At Ferrari, he worked on several version of the successful 250 models. He worked in particular on the Ferrari 250 TR, 250 GT Short Wheelbase and the 1962 Ferrari 250 GTO. He left Ferrari on occasion of a "palace revolt" with the boss. He was among the group of engineers including Carlo Chiti, Romulo Tavoni and Gardini who walked away from the Maranello factory.

Bizzarini with the collaboration of Neri and Bonaccini for the mechanical development  as well as Piero Drogo for the coachbuilding developed a few upgraded Ferrari 250 GT SWB with more power, less weight and lower body profile for private competitors.

Here is the Ferrari 250 GT SWB Special "Breadvan" prepared by Giotto Bizzarini and Piero Drogo for Count Volpi de Misurata for 1962 Le Mans 24 Hours.

One of these special 250 GT SWB is the famous modified Ferrari 250GT SWB "Breadvan" for Count Giovanni Volpi de Misurata Scuderia Serenissima prepared for Le Mans 1962

Giotto Bizzarini participated at the development of the new ATS Company  with financial support from the same Count Volpi. ATS was involved in Formula One and 2500 GT Coupe mid engine  berlinetta.

Giotto Bizzarini then started his own engineering company Autostar at Livorno. In this situation he developed a 3.5 Litre V12 engine for Ferruchio Lamborghini . It became the base for the start of development of Lamborghini.

Giotto Bizzarini also collaborated for Renzo Rivolta who wanted to diversify his industrial activities with the production of  high performance automobiles using mass production powerful American V8 engines rather than sophisticated own Italian V12.
The first model was introduced at 1962 Turin Motor Show and was Iso Rivolta IR300 a four seats grand touring coupe with body style prepared by Giorgetto Giugiaro for Carrozzeria Bertone. The Iso Rivolta was propelled by a Chevrolet Corvette V8 engine.

ISO Grifo A3 Lusso 1963 at Pebble Beach

In 1963 the ISO Company introduced at the Turin Motor Show two new two seats short wheelbase coupes, the Iso Grifo A3L for Lusso and the Iso Grifo A3 C for Competition. Both cars presented specific body styles prepared once again by Carrozzeria Bertone with styling design by Giorgetto Giugiaro.

1964 ISO Grifo A3C and Bizzarini 5300 GT - original factory photos

Apart from their wheelbase, which has been brought down from 270 cm on ISO 4 seats IR300 to 245 cm on Grifo coupes, the Grifo A3 Lusso and the Grifo A3C have the same general structure in an integrated platform chassis made of steel sheet electrically spot welded. The suspension also remains the same.

The engine is the 5.4 Litre V8 of the Chevrolet Corvette giving up to 365 hp in standard version with a single four-barrel carburettor. The most powerful version produces 405 hp with four Weber 45 DCOE carburettors. The transmission utilizes a four speed manual gearbox.

The independent front suspension is by wishbones, coil springs , telescopic dampers and an anti roll bar. At the rear there is a de Dion axle with coil springs, hydraulic dampers, longitudinal struts and an anti roll bar. The car is equipped with four disc brakes. The rear suspension was changed to independent suspension with in-board disc brakes on the latest Bizzarini  America examples ; in these cars the engine was upgraded to a maximum 420 hp.

In the ISO Grifo A3C and Bizzarini 5300 GT the engine is placed in "front-mid-engine" position behind the front axle and so much back in the car that there is a trap on the dashboard to access the distributor. A dry sump lubrication system allows to place the engine in a low level improving the position of the centre of gravity and allowing a more streamlined body shape at the front.

The competition oriented body of the first versions is made by riveting steel element with duralumin and aluminium that is the only assembly technique for such a diversity of materials. The body was assembled by Carrozzeria Drogo.

The performance claimed by the factory for an ISO Grifo A3 Corsa was 300 kph (186 mph)  in top speed and 5.6 seconds for 0 to 100 kph (62mph). with 405 hp engine. The 0 to 160 kph (99 mph) was announced  in 14 seconds.

When Renzo Rivolta deceased in 1963, his son took over  the production of ISO Rivolta cars. Giotto Bizzarini stopped his collaboration with the Company and obtained the license to pursue the production of the A3C on his own brand name thus initiating the story of the Bizzarini 5300 GT Stradale or Competition version. The body and frame of the Bizzarini was completed by Sports Cars in Modena with welded aluminium rather than previous riveting technique.

The ISO Grifo A3C was produced in 23 examples including 16 Stradale road legal automobiles. At the end of production in 1968 , 110 Bizzarini 5300 Gt have been produced. The Bizzarini 5300 America was equiped with glass fibre resin composite bodies.

A few track references

1968 Bizzarini 5300GT Strada sold for Euros 1.244.400- at Artcurial Auction during Retromobile Paris 2015

A few auction sales references

Gooding & Company Pebble Beach 2008- 1967 Bizzarini 5300 GT Strada Alloy sold US$ 517.000
RM Villa Erba 2011- 1968 Bizzarini 5300 GT Strada sold for Euros 400.000

ARTCURIAL 2015- 1968 Bizzarini 5300 GT Strada sold for Euros 1.244.400
RM Sotheby Paris 2015 1965 ISO Grifo A3C Stradale sold for Euros 1.036.000

P.Damiens-Reference-Source-Photos P.and K. Damiens and Philippe Girardon
Source:- Ferrari The Sports and Gran Turismo Cars Fitzgerald , Merritt & Thompson CBS Publications 1972
-Iso Grifo A3C John Bolster Autosport August 14 1964
-Iso Grifo A3C AutoPassion Juillet 1991
-1964 Three ISO Grifos -Etienne Cornil  Sporting Motorist September 1964
RM Sotheby, Bonhams, Artcurial and Gooding & Co  Archives

Le Mans Official History 1960-69, Quentin Spurring, Haynes

Wallpapers of Iso Grifo A3C and Bizzarini 5300 GT 1963-1968 (Clik on image to enlarge)