After Giotto Bizzarrini left Ferrari in 1961 he was hired by Renzo Rivolta to design and construct cars for the ISO marque in Milano i.e ISO Rivolta, ISO Grifo A3L (Lusso) and ISO Grifo A3C (Competition/Corsa).The L and C versions were both exhibited at Torino Auto Show Nov 1963. The A3C made its debut in the12 hours of Sebring March 1964 and carried on competing in the World Championship long distance races against Porsche 904, Daytona Cobra, Jaguar E, Ferrari GTO, Aston Martin, Chevrolet Corvette and others all through 1964 and 1965. Even though the car was not homologated but a prototype. However, Rivolta wanted to build cars to sell so a deal was made where they split and Bizzarrini continued on his own with the racing activities and building cars to sell to finance the racing under his own name and he did so with relative success. This is why a car basically with the same features appears with different names, ISO Grifo A3C, Bizzarrini Grifo, Bizzarrini Strada, Bizzarrini America, and with different chassis numbers prefix, B, IA3, and BA. The company was plagued with economical difficulties and closed its doors in Sep 1968. At the time of the bankruptcy, it is believed 124 cars of this type had been built.

Note that this page is applicable for the Bizzarrini 5300 GT as well.