|Manufacturer||Iso Autoveicoli S.p.A.|
|Designer||Giorgetto Giugiaro at Bertone|
|Body and chassis|
|Body style||2-door coupe|
|Transmission||4-speed Muncie or 5-speed ZF manual transmission |
3-speed automatic (on request)
|Wheelbase||98.4 in (2,499 mm)|
|Length||174.4 in (4,430 mm)|
|Width||69.7 in (1,770 mm)|
|Height||47.2 in (1,199 mm)|
|Curb weight||3,150–3,550 lb (1,430–1,610 kg)|
The Iso Grifo is a limited production grand tourer automobile manufactured by Italian Iso Autoveicoli S.p.A. between 1965 and 1974. Intended to compete with Ferrari and Maserati GTs, it utilized a series of American power trains and components supplied by Chevrolet and Ford to ensure performance and maximize reliability. Styling was done by Giorgetto Giugiaro at Bertone, while the mechanicals were the work of Giotto Bizzarrini.
The first production GL models appeared in 1965 and were powered by American Chevrolet Corvette small-block 327 (5.4-litre) V8s fitted to American supplied Borg-Warner 4-speed manual transmissions. The 5.4-litre engine developed 300 hp (220 kW) in its standard form and could reach 110 km/h (68 mph) in first gear.
In 1970, the Grifo Series II appeared, with sleeker styling and hide-away headlights and powered by big-block Chevrolet 454 V8 (7.4-litre) engines. It was replaced in 1972 with the Grifo IR-8, which utilized a small-block Ford Boss 351 engine (5.8-litre) as its power train. This was the last new Iso of any type, as the manufacturer went bankrupt and eventually shut down and ceased all operations permanently in 1974. The bankruptcy had a number of causes, perhaps the largest being the 1973 oil crisis which significantly reduced demand for cars with large V8 engines.
Iso S.p.A. in Bresso was already well known for producing the high performance Iso Rivolta IR 300; a sleek looking 2+2 Coupe based on a Chevrolet Corvette power and drive train. After leaving Ferrari, in 1961 Giotto Bizzarrini set up “Prototipi Bizzarrini” in Livorno, Tuscany where he designed and consulted for marques like ATS, Lamborghini and Iso. In 1963, he designed the Iso Grifo A3/L ("L" for Lusso, Italian for "luxury") for Renzo Rivolta, who was looking for a follow-up to his IR 300. The body was designed by Giorgetto Giugiaro at Bertone, while Bizzarrini put his expertise in the mechanicals. Bizzarrini figured there would also be a demand for a race version of the Grifo and came up with the A3/C (C for Corsa) with a dramatic modified alloy body. He later dubbed it his “Improved GTO", as he had been the designer for the 250 GTO when he had worked for Ferrari. The engine was moved back about 40 mm (1.6 in), making the A3/C a front-mid-engined car. To adjust the timing a piece of the dash was removed. Both cars were being built simultaneously. When leaving the factory both the 250 GTO and Iso Grifo originally fitted Pirelli Cinturato 205VR15 tires (CN72).
At the Turin Motor Show that same year, Bertone showed the Grifo A3/L prototype while Iso showed off 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 racer performed very well despite it being 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 while the car received a modified but reliable Chevrolet small-block 327 Corvette engine V8 (5.4 L) engine—either in 300 or 350 hp—coupled to a Borg-Warner 4-speed top-loader. The engines were completely ordered and manufactured in the United States, then taken apart and blueprinted before they were eventually installed in the cars, much like it was done with the IR 300. With over 350 hp (260 kW) and a weight of less than 2,200 lb (1,000 kg), the vehicle was able to reach speeds over 275 km/h (171 mph).
In 1964, the prototype A3/C raced at Le Mans (Edgar Berney/Pierre Noblet), running well until brake problems required a two-hour pit stop. The car then resumed the race, finally finishing 14th. However the race in 1965 proved to better for the A3/C, finishing 9th.
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, which resulted in separate production of the Grifo GL and the competition Bizzarrini A3/C. The Grifo GL was being produced at Bresso while the A3/C was produced at Piero Drogo’s Sports Cars of Modena under Bizzarini's strict supervision. Bizzarrini refined his A3/C and this eventually turned out to be his line of Bizzarrini 5300 Stradas and Corsas. Only 22 examples of the Grifo A3/C were constructed before Rivolta and Bizzarrini split.
In October 1966, the very first Grifo (car #97) with a targa top was shown at the Turin Motor Show. This was one of only thirteen Series I Targas ever built; later, only four series II Targas were built.
In 1968 the Grifo 7 Litri was introduced with a Chevrolet L71 big-block engine, a Tri-Power version of the 427 engine. The massive power plant required several mechanical changes to the car in order to fit, i.e. strengthened chassis components as well as an enlarged engine compartment with reinforced mounts. A large hood scoop (dubbed "Penthouse" due to its size) was added to clear for the engine's deck height. It produced an officially advertised minimum of 435 hp (324 kW) at 5800 rpm, which was a somewhat conservative rating given the engine's well known and proven performance potential. The factory claimed it could reach a top speed of 300 km/h (186 mph).
In 1970, a styling change was made to the nose section of the car for the Grifo Series II, It got a sleeker look and hide-away headlights. In the IR-9 "Can Am" version the engine was switched from the 427 engines to the newer even more powerful Chevrolet 454 7.4 litre engine.
In 1972, the Grifo IR-8 was released, using a small-block Ford Boss 351 engines. These models can be recognized by their taller hood scoop. This was the final version of any Iso automobile, as Iso S.P.A. closed its doors in 1974 during the 1970s oil crisis.
In total, 322 Series I and 78 Series II cars were built for a total of 413 Grifos, 90 of which were 7-litre. The rarest are the Series II 5-speeds (23 units) and the Series II Targa (4 units). Due to their rarity today Grifos are desirable collectibles. A former employee of Iso, Roberto Negri, runs a small company in Clusone, Italy, specializing in maintaining and restoring Grifos. There is a global community of Iso Grifo owners around the world, and they have gatherings a number of times each year.
- Buckley; Rees. p155
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