1963 ISO Grifo A3/L

The legacy of Iso Autoveicoli S.p.A. stretches to before the onset of World War II, and over the years has been known as Isothermos, Iso Rivolta, and Iso Motors. Among their contributions to the local and global economy were electric heaters, chillers, motorbikes, scooters, and various types of motorcars including the microcar. The company was founded by a visionary and engineer named Renzo Rivolta who kept pace with the pulse of the market. In the years immediately following World War II, he recognized the potential for an affordable means of transportation in Italy and all of Europe. This prompted the production of scooters, motorcycles, small trucks, and the Isetta mini-car. BMW would later acquire the license for the Isetta microcar and its popularity led to the company's re-establishment of financial stability. Iso would eventually explore the Gran Touring (GT) car production by combining Italian styling with American power. The pinnacle of the Iso GT cars was the Grifo with styling by Giorgetto Giugiaro of Bertone and engineering by Giotto Bizzarrini, the lead engineer for developing the Ferrari 250 GTO.

The Iso Grifo
The Iso Grifo was produced between 1965 and 1975 with 330 examples of the Series I and 83 of the Series II. Of the 413 examples created, 90 were equipped with seven-liter engines, 23 examples of the Series II had a five-speed gearbox, and four Series II cars had a Targa top.

The Grifo joined the Iso Rivolta grand tourer which had been introduced in 1962 and would remain in production through 1970. It was a 2+2 coupe 'family car' that used a 5.4-liter Chevrolet 327 V8 engine, wore a design by Giugiaro, and benefitted from the engineering expertise of Bizzarrini and Pierluigi Raggi. This was the first luxury automobile introduced by the company and a total of 797 examples were built during its production lifespan. It used pressed steel and a welded panel chassis with a wheelbase size of 2700mm (106.3 inches) and a length of 4,760 mm (187.4 inches). Its suspension was a de Dion setup in the rear with unequal-length wishbones in the front. Disc brakes all round provided the stopping power.

The Grifo had sportier styling than the Rivolta and its wind-cheating design was built for both the road and the track. The Iso Grifo A3/L ('L' representing Lusso, Italian for 'luxury') was the road-going luxury version while the A3/C (C for Corsa) wore an alloy body, had its engine moved back about 40mm (1.6 inches), and intended for competition.

The Grifo rested atop a shortened version of the Rivolta GT chassis that measured 2499mm (98.4 inches) and a length of 4430mm (174.4 inches). Nuccio Bertone built the prototype example based on the rolling chassis and mechanical components supplied by Iso. The Grifo A3/L concept car was introduced in 1963 on the Bertone stand at the Turin Auto Show while the race-bred, unpainted Iso Grifo A3/C was on the Iso stand at the same show. The production version of the Iso Grifo A3/L received a few styling changes and its name was changed to the Iso Grifo GL. Both versions would become successful in their own right, including a class victory at the 24 Hours of Le Mans two years later by the A3/C.

Initially, both cars were equipped with Chevrolet Corvette 327 cubic-inch V8 engines backed by a Borg-Warner 4-speed manual transmission. The limited-slip differential was a Salisbury unit, and both used the same chassis. The engine location in the A3/C improved weight distribution and is considered a front-mid-engine placement. With the engine residing farther forward in the GL (albeit well behind the front axle), interior space was improved which catered to the luxury persona. The Grifo GL wore a steel body with an aluminum hood and the A3/C used aluminum components wherever possible. The single carburetor on the engine was replaced with four side-draft Weber carburetors, and along with tuning of the intake rams, improved output to around 400 HP. The potent engine, combined with its 2,750-pound weight (compared to 2,970 lbs of the A3/L), the A3/C was capable of 170 MPH.

Just like the engines installed in the RI 300, each unit was taken apart before they were installed in the cars. The 327 CID V8 had overhead valves, a single Carter 4-barrel carburetor, and developed approximately 340 horsepower at 6,000 RPM. In 1968, Piero Rivolta created a more powerful version of the Grifo by installing a Corvette 427 cubic-inch L71 big-block engine with Tri-Power creating a new model named the Grifo 7 Litri. The engine was much larger and more powerful than the 327 V8 requiring several design and mechanical modifications. The hood received a large scoop, dubbed 'Penthouse' due to its size, which accommodated the engine's deck height. In this guise, the engine offered 435 horsepower at 5,800 RPM and had a top speed of 186 mph.

The Grio Series II cars of 1970 received styling changes to the front including the addition of hide-away headlights. The IR-9 'CanAm' version used the newer Chevrolet 454 7.4-liter engines instead of the 427 engines. The Grifo IR-8 of 1972 was equipped with a small-block Ford Boss 351 engine with an even taller hood scoop.

Bizzarrini Strada
The Bizzarrini Strada (also known as the 5300 GT) was built from 1964 through 1968, with 133 examples created. It began as an Iso, but disagreements between Bizzarrini and Rivolta brought a separation of these two companies. Iso retained the rights to the Grifo name and Bizzarrini obtained the rights to build the A3/C, plus mechanical components to build a limited number of examples. Named the Bizzarrini 5300 GT, it was available in either Strada or Corsa trim. It used the welded unibody platform of the Iso Rivolta 300 and was equipped with the 5.4-liter Chevy V8 engine. Along with the two-door coupe configuration, three spyder versions were also built, including the prototype with a full convertible top and two production versions with removable T-Tops.

by Daniel Vaughan | Sep 2021