Iso Grifo: American fist in an Italian glove
“Hardly any road cars in the mid-60s were capable of pulling 60mph in first gear and onto a top speed of 186mph-plus in the final version – all without fuss. Grifos weren’t temperamental, didn’t overheat, they were robust, spare parts were readily available and they did not require the ministrations of a 12-fingered Italian ingegnere to maintain them. All this, encased in drop-dead gorgeous hand-built Italian coachwork.”
What’s not to love? As Carligious reminds us, reflection often increases appreciation of cars which were under-appreciated when new - think Porsche 928. The “drop-dead gorgeous” Iso Grifo GL manufactured between 1965 and 1974 with Chevrolet and later Ford V8 power is another example of a rare classic which, although rapidly increasing in desirability and value today, was snubbed by many during its prime.
In this case, solely due to its ‘mongrel’ Italian-American heritage. No pedigree, the purists would snort, blissfully ignorant of the fact that European cars with American engines share a unique lineage – dare we say bloodline - stretching back to the earliest days of the automobile; from countless Model T-powered specials in the 1910s and 1920s to the Hudson-Railtons of the 1930s, Cadillac-Allards and Facel Vegas of the 1950s, AC Cobras and Sunbeam Tigers of the 1960s, De Tomaso Panteras and Jensen Interceptors of the 1970s to name a few.
Fact is, for those fortunate enough to drive a Grifo the way it was designed to be driven during its prime, any posturing over so-called pedigree was dismissed once its American V8 erupted into life and the sublime supercar performance could be appreciated.
“That the Iso Grifo could start up its Chevy engine and crash the luxury GT party is Lucius Beebe material. What could be more outrageous? A wash-and-wear suit with a Cardin label? A&P or Safeway caviar? The purists have been had,” mocked Car and Driver in reviewing the Grifo in 1968.
“So far as we’re concerned, pedigree doesn’t mean a damned thing when it comes to the worth of an automobile – unless you have a car you can’t stand driving and you have to talk about it instead. How many automotive genealogists are driving new Bugattis or Duesenbergs these days? The Iso Grifo, son of a refrigerator, may have a very different origin but it’s sitting where it belongs – at the head table.”
That crack about its refrigerator parentage was in reference to Italian industrialist Renzo Rivolta, father of the Grifo who established his commercial refrigeration and heating company Isothermos in Genoa in 1939 at the onset of war in Europe. After Allied bombing raids destroyed the company’s premises, Rivolta moved his operation north to Bresso near Milan.
Immediately after the war Rivolta expanded into motor-scooter production, to meet unprecedented demand for cheap mobility in a shattered post-war Europe. His highly profitable Bresso plant was soon Italy’s third largest domestic two-wheeled manufacturer behind Vespa and Lambretta.
Rivolta expanded into motorcycles and by the early 1950s his company had been renamed Iso Autoveicoli (motor vehicles) to reflect its growing automotive interests. With cheap transport still in high demand, Rivolta envisaged a vehicle that was as economical as a motorcycle with the greater protection of a car.
The end result was the iconic egg-shaped Isetta (little Iso), effectively a four-wheeled cabin scooter that was not a great success in Italy as small buyers largely preferred Fiat’s Topolino. However, the Isetta did prove a hit in other markets when built under license; the most notable and iconic of those manufacturers being BMW which the humble Isetta saved from near-certain extinction.
Laying the foundations
Towards the end of the 1950s, with Europe having finally shaken the shackles of its post-war austerity, Rivolta had grand visions of joining the likes of Ferrari and Maserati in producing high performance grand touring cars under his own name. His primary focus was the lucrative US market.
He had owned a number of exotic GTs but was never satisfied with any of them and increasingly irritated by their expensive maintenance and poor reliability. It was while attending the Frankfurt Motor Show in 1961 that he overheard a conversation between two Americans, one being US prestige car importer Max Hoffman, in which they agreed that a European GT with an American engine would be ideal for the US market. That planted a seed in Rivolta’s fertile mind.
By that stage his company had been renamed Iso Rivolta and plans to create his unique GTs started to move from dream to reality. And in that context, there were several artisans that were key to the Grifo’s creation.
Renzo Rivolta’s passion for life in the fast lane, “at the wheel of a car I can only enjoy myself above 120mph” he’s quoted as saying, provided not only the funding and manufacturing facilities but also the bold vision of an Italian GT with US muscle. Rivolta was enamoured by the Bertone-bodied 1959 prototype Gordon GT, that evolved into the Gordon-Keeble, which was studied closely and from which much inspiration was drawn.
Another was Iso’s chief technician Pierluigi Raggi in charge of chassis design, along with consulting engineer and former Ferrari employee Giotto Bizzarrini. The latter’s most notable achievement at Maranello was design and development of the immortal 250 GTO. After the infamous Ferrari walk-out in 1961, he consulted for Italian industrialist Ferruccio Lamborghini on the design of a quad-cam V12 for another new Italian GT that would carry his name, before Giotto's engagement with Iso.
The final piece in this personnel puzzle was the sublime stylist Giorgetto Giugiaro, who was just starting his decorated career at Bertone when he created the handsome Iso Rivolta GT (aka IR 300).
Unveiled in 1962, it was an impressive first attempt at a muscular grand tourer by the Bresso manufacturer. Elegant styling combined with comfortable seating for four adults, surefooted handling and exhilarating 140mph (224km/h) performance was well received judging by contemporary road test reports, particularly in US journals.
Of most significance for this story, though, was its unusual steel sheet chassis and all-American GM drivetrain comprising a 300bhp Corvette 327 V8, Borg Warner T-10 four-speed gearbox and chassis-mounted Salisbury limited-slip differential, which with minor revisions would also underpin the Grifo.
At the Turin show in 1963 the motoring world got its first glimpse of the new Iso Grifo A3/L prototype. The name grifo, Italian for griffin, was most appropriate for this gorgeous two-seat berlinetta, as the mythical creature had a healthy appetite for horses - think Ferrari!
It was indeed a fabulous-looking machine “clothed by Nuccio Bertone with a body of impeccable harmony” according to Sporting Motorist, another masterpiece from Giugiaro’s drawing board. And its chassis, derived from the closely-related Rivolta GT, was again the work of Raggi and hired gun Bizzarrini.
There were, in fact, two prototypes on display at Turin, both designed by Giugiaro. One was the A3/L with the L denoting Lusso (luxury) and the other was a lightweight competition version championed by Bizzarrini, presented with unpainted aluminium bodywork attached to its steel frame by pop-rivets. Called the A3/C with the C denoting Corsa (race), it stood only 43 inches or just over one metre tall with its 327 V8 engine moved even further back in the chassis.
At that stage Rivolta had no production plans for either of these concepts; he commissioned them primarily to gauge public reaction and bask in the excitement they created to increase sales of his established GT model. Around this time Bertone also produced a stunning one-off spyder version of the A3/L prototype, which sadly was not offered as a regular production model.
In 1964 Bizzarrini oversaw construction of some Grifo A3/Cs in both road and race specifications. Being an ex-Ferrari man, he passionately believed that to successfully sell road cars, Iso had to be involved in top-level motor racing. The A3/C was a project close to his heart and after winning its class at the Le Mans 24-Hour that year, first time out, Bizzarrini saw nothing but potential. It won its class again and finished ninth outright at Le Mans in 1965.
Problem was, Renzo Rivolta, like new rival Lamborghini who had recently unveiled his 3.5 litre V12-powered 350 GT, did not share Bizzarrini’s racing passion nor vision. Renzo quickly lost interest in backing such an unprofitable activity and they inevitably parted ways.
According to Sport Car Graphic, a license was negotiated under which the A3/C model was built, starting in early 1965, solely by Giotto’s small Prototipo Bizzarrini works. At first Giotto kept the Grifo name but later in 1965, Rivolta decided to put the beautiful A3/L model into production and the name was dropped. Bizzarrini continued to produce small numbers of these cars, bearing his own name, until his cash-strapped company closed its doors in 1968. Giotto was a brilliant engineer, but a poor businessman.
Iso Grifo GL Series I
The Iso Grifo entered production in 1965 as the GL (Grande Luxe) with mild revisions of the showstopping Turin prototype. Built on a derivative of the Rivolta GT platform, the new two-seater’s 2500mm wheelbase was almost 200mm shorter and its slightly rearward 49/51 weight distribution was unusual for a car with a cast iron V8 but most desirable in handling terms.
According to Renzo Rivolta’s son Piero, when interviewed by Motor Trend Classic, Raggi’s chassis concept was designed with series production in mind:
“Raggi thoroughly investigated what the competition was using - a tubular chassis – and saw how the cars were made. Because we would have to sub-contract chassis production, he felt we wouldn’t get the quality we desired. We came from a background where something had to work without problems or faults, squeaks or noises. Raggi thought a platform chassis welded to the body offered that and was more suited for the production numbers we envisioned.”
The Raggi/Bizzarrini chassis was fabricated from stamped sheet steel that was spot-welded together into a robust tub with boxed side and rear members plus a large transmission tunnel providing excellent rigidity. The all-steel body, initially supplied by Bertone until Iso took this work in-house, was then welded onto this platform to create a robust unitary body-chassis unit.
Front suspension was wishbones with coil springs while the rear used a coil-spring De Dion tube located by upper and lower trailing arms and a Watts linkage. There were four disc brakes of course, the rears mounted inboard to minimise unsprung weight, while steering was via recirculating ball. Wheels were handsome 15-inch Campagnolo alloys with Pirelli Cinturato HS tyres.
The low, wide and voluptuous Grifo coupe, with functional vents behind the front wheels to extract engine bay heat, was just over 4.4 metres in length and 1.7 metres in width. It stood just 1.2 metres tall with a dry weight of 1300kg. 13 rare Targa-roof variants were also produced.
Car and Driver was effusive about the styling: “Artists like Giugiaro enjoy demonstrating their expertise by pulling subtle visual tricks on unskilled eyes. The Grifo’s biggest trick is the broad, dull-finished rocker panel which interrupts the body colour, giving the illusion of extreme lowness.”
The Grifo offered two states of engine tune, with a choice GM Muncie M21 four-speed manual or GM two-speed Powerglide or three-speed Turbo-Hydromatic autos.
The milder version of the Corvette 327 V8 with 10.5:1 compression, hydraulic lifters and Carter four-barrel carb was rated at 300bhp (gross) and capable of a claimed 140mph (225km/h) top speed. The hottest with 11:1 compression, mechanical lifters and Holley four-barrel punched out 365bhp (272kW) at 6200rpm and 360ft/lbs (488Nm) at 4000rpm.
Magazine tests of the 365bhp version produced high 14-secs standing quarters, 0-100km/h in just 6.0 secs and 0-160km/h in 14.8 secs with a 160mph-plus (256km/h) top speed. In other words, phenomenal acceleration superior to a GT-HO Phase Three with 20mph (32km/h) more top-end!
Autocar achieved a genuine 161mph (258km/h) making it the fastest road car the magazine had tested to that point. It was demonstrably superior to contemporaries including the Aston Martin DB6, Jaguar E-type 4.2, Jensen C-V8 and Ferrari 330 GT which all could not top 155mph (248km/h) in Autocar tests. Fact is, the Grifo GL was one of the world’s fastest road cars.
Piero Rivolta: "A 365hp Grifo could do 161mph so it was popular because how fast your car went was a very big deal. People compared top speed at cocktail parties, so whether you went from Turin to Milan in 31 or 32 minutes was really important. If your car goes faster and doesn't break when you close the hood, you don't care what you have inside. Faster is faster!"
In Iso tradition, the imported American V8s weren’t just lifted from shipping crate to engine bay as the so-called purists would have you believe. Each Grifo engine was completely dismantled, inspected and reassembled by hand and hot run-tested at Bresso before installation.
Iso engineers also found a solution to some early engine failures suffered by German owners at high sustained speeds on autobahns. The cause was traced to hairline fractures appearing in the stock GM connecting rods, so Iso forged its own stronger replacements and installed a larger capacity cast-aluminium finned sump (also of Italian manufacture) to improve lubrication, which solved the problem.
The motoring press was clearly impressed by the Grifo’s quality, comfort and performance.
Autosport: “There is ample leg room and foot space for the driver and passenger in consequence and the standard of construction of the body is truly excellent. The doors shut decisively with the pressure of two fingers and very little sound. The whole structure is completely rigid with never a hint of a squeak or rattle, irrespective of the road surface.”
Car and Driver: “You treat the steering and throttle like hair triggers when cornering at high rates with the Grifo, because it responds more and faster than you might expect. A very rewarding car for the skilful – all others should work up to it gradually.”
And Autocar:“Anyone condemning speed has not travelled in a thoroughbred like the Grifo, which takes so much in its stride without having to exert itself or the driver. Opportunities for overtaking present themselves at least twice as often in the Grifo, so dynamic is the acceleration.
“Although our testers are used to high performance cars, all were impressed by the lightning response to the accelerator in any gear. Overtaking manoeuvres could be completed in little more time than it would normally take to assess the situation and make a decision.
“A good test of a sports car is how happy or otherwise the passengers feel when being rushed along. In the Grifo everyone seems content to sit back and enjoy the thrill, barely believing (when told) the speeds they are travelling at, so quiet and effortless is the progress.”
Sadly, Renzo Rivolta would not get to bask in the glory of his widely revered creation for long, as he died from a heart attack in 1966. His unexpected death sent a shockwave through the company but fortunately his son Piero, a qualified engineer only then in his mid-20s, was able to seamlessly take over management of a factory in which he had literally grown up, learning all about the business as he went.
Under Piero’s management, in 1967 the Grifo was available for the first time with an optional ZF five-speed gearbox which with its overdriven fifth gear ensured not only more effortless top-end performance but also quieter cruising and improved fuel economy.
Another first-time Grifo option for 1967 was air-conditioning. According to contemporary road testers it worked superbly on even the hottest days, but then how could they have expected anything less from a company that was founded in the manufacture of commercial refrigeration equipment!
1968 saw the introduction of the monster Iso Grifo 7 litre or 7 Litri variant, with 427 cubic inches of Chevrolet big block V8 squeezed into the engine bay. Due to the engine’s increased size and weight, engineering changes were required including beefed-up chassis rails and engine mounts.
It also required a long, flat and low bonnet intake known as the ‘pagoda’ or ‘penthouse’ to provide adequate under-bonnet clearance and enhanced breathing. Although this distinctive - some would say crude - device disrupted the purity of Giugiaro’s original lines, it had good functionality and certainly added a look of menacing intent.
These monster 427s were given the same hands-on treatment as the 327s. Naturally, this 100cid cast iron increase in cubic displacement also came with a weight penalty, but such concerns were obliterated by the brute force under the bonnet.
The 7 Litre was conservatively rated at 400bhp (SAE) at 5200rpm, but the reality was closer to 425bhp (317kW). Torque was bulldozer-grade with 460ft/lbs (624Nm) at 3600rpm. Its staggering official top speed was 186mph (298km/h) – and that was in 1968! However, it was never put to the test against a stopwatch or electronic timing device by an Autocar, Car and Driver or Road and Track at the time, which has only increased the mystery of this rare supercar.
“Turning the key and firing up that huge V8 brings a roar the like of which few drivers will ever hear. It is a mean sound, a menacing tone. You can almost see the two big exhaust pipes spitting fury,” wrote Mel Nichols in his test of a three-speed auto-equipped 7 Litre Series 1 for Sports Car World in 1973.
“Soon, you learn that being timid with the car will not do. It is a heavy front-engined sports/GT, the steering is heavy and it needs a lot of its available power poked into the rear end to get it operating properly. (Power oversteer in other words!)
“You get out of it trembling a bit. Its excitement is strong and your reflexes have to be keyed up tight to work it. It’s that sort of car. A big, fat, strong brute. Be timid with it, afraid to take a whip to those 400 horses, and it will despise you; maybe even eat you. But be tough and firm and stand right over it and it will obey you and serve you with relish.”
Iso Grifo Series II
The launch of the Series II in 1970 brought revisions to the Grifo’s styling, most noticeably a longer and more sloping nose, narrower grille and shrouded headlights, evidently to improve aerodynamics. Headlight ‘eyelids’ would flip-up to reveal the full lights when in operation.
The 327 IR8 and 427 IR9 Can-Am variants, some with 454cid (7.4 litre) Chevrolet V8s, continued in production until 1972, when the company switched to Ford’s 351cid (5.8 litre) 4V Cleveland V8 and Cruise-O-Matic auto transmissions after GM imposed onerous commercial conditions on its drivetrain supply. Estimates vary, but the 351 was good for around 380bhp and 160mph performance. The penthouse added another storey to provide extra clearance for the taller Ford engine.
However, by the end of 1973, the newly renamed Iso Motors was facing an existential crisis, even though it was by then producing numerous models including the luxurious Fidia sedan and Lele 2+2 grand tourer models.
Tougher US vehicle safety and emissions compliance, changing public attitudes towards ostentatious GT cars and the world’s first oil crisis created a perfect economic storm that the cash-strapped company could not survive. Its factory doors closed the following year, when the last Ford-powered Grifo rolled off the line.
After a decade of production, just over 400 Iso Grifos were produced although opinions vary on the exact final number. In any case, the Iso Grifo is a rare and increasingly desirable classic. Perhaps Autosport’s John Bolster in 1966 best encapsulated all that was great about this car:
“The Grifo GL365 excels because exactly the right compromise has been struck. This is a car with awe-inspiring speed and shattering acceleration which is perfectly at home in London’s worst traffic or taking my lady to a ball at the Dorchester.
“I admire the Iso Grifo because it is beautiful and because superb craftsmanship and excellent finish are apparent in every detail. I enjoy its tremendous performance because it has roadholding and brakes to match. Perhaps as much as anything I appreciate its silence, the lightness of its controls and its good manners…for the man who wants the ultimate in two-seaters, this is the best that money can buy.” And those purists be damned!