originally fitted with Pirelli Cinturato 205VR15 tyres (CN72). At the Turin Motor Show that same year, Bertone showed the Grifo A3/L prototype while Iso unveiled the unpainted competition version: the Iso Grifo A3/C. Both became successful in their own right, the road car receiving praise from the press, while the race car performed very well although it had been made on a much tighter budget compared to Ferrari. Rivolta also showed a prototype A3/L Spyder at the Geneva Motor Show. Grifo GL – Bizzarrini A3/C split Iso concentrated on getting the A3/L ready for production, concentrating on some of the design changes that had to be made to the prototype. The car got a light face-lift that made it less aggressive in appearance. It was given a modified but reliable 5.4 litre Chevrolet small-block 327 V8 engine—having variable power outputs of —coupled to a Borg-Warner 4-speed manual transmission. The engines were completely ordered and manufactured in the United States; they were shipped to Italy, where they were taken apart before they were eventually installed in the cars. This was similar to the manufacturing process of the IR 300. With a weight of less than , the car was able to attain a top speed of over . In 1964, the prototype A3/C raced at Le Mans (driven by Edgar Berney and Pierre Noblet), running well until brake problems required a two-hour pit stop. The car resumed the race, finally finishing 14th. In 1965, the car performed better, finishing 9th at Le Mans. The production of the Iso Grifo GL started in 1965, but the Bizzarrini and Rivolta partnership quickly fell apart over the use of the name Grifo. This resulted in separate production of the Grifo GL and the competition Bizzarrini A3/C. The Grifo GL was produced at Bresso, while the A3/C was produced at Piero Drogo’s Sports Cars of Modena, under Bizzarrini's strict supervision. Bizzarrini refined his A3/C , eventually developing his line of models. Only 22 examples of the Grifo A3/C were made before Rivolta and Bizzarrini split. Model year changes In October 1966, the first Grifo (car #97) with a targa top was shown at the Turin Motor Show. Designed by Bertone and featuring the stunning removable roof, the reliable 300 hp Chevy 327 V8, and the coveted ZF 5 speed transmission. Only fourteen Series I Targas and four series II Targas were built. In 1968 the