www.QV500.com - Iso A3/C & Bizzarrini 5300 Part 2: The Iso A3/C
 

Iso A3/C Stradale - note the Bizzarrini badge 		Featuring a combined multi-tubular semi-monocoque chassis, the A3/C frame was derived from Iso's A3/L Grifo, albeit with a reinforced floorpan and a wheelbase shortened by Piero Drogo’s Sports Cars of Modena. Reduced from 2700 to 2450mm, the A3/C chassis was also much lighter than the Bertone-bodied A3/L frame and had its engine mounted well back for optimum weight distribution. The motor was actually positioned so far back that access to the ignition and distributor was via a trap door located on top of the dash.
   
Furthermore, Bizzarrini's drive towards ideal weight distribution also influenced the fuel tank location, two side-mounted saddle tanks being joined by a third located directly behind the front seats. Eventually, Bizzarrini finished up with an impressive 52/48 front/rear split. Independent front suspension was by double triangulated wishbones and helical springs with telescopic dampers and an anti-roll bar, the rear featuring a de Dion axle, paired parallel radius arms and a lateral Watt’s linkage. Two alternative ratios were available for the Burman recirculating ball steering box, braking coming via Dunlop discs with the rear units inboard of the differential. Bizzarrini chose beautifully fabricated Campagnolo knock-off cast alloy wheels shod with either Dunlop R6/R7 racing tyres or Dunlop SP/Goodyear Blue Streak rubber for the A3/C. Corsa versions weighed in at around 1220kg while the Strada's were slightly heavier at 1270kg. Rather than design and construct scratch built motors like Ferrari, Maserati and Lamborghini, Iso preferred to use large capacity, ultra reliable and extremely powerful American V8's for his cars. The A3/C used a Chevrolet 327cu V8 prepared in-house to either 405bhp in Corsa trim or mildly de-tuned 365bhp Strada spec. Displacement was always 5354cc thanks to a bore and stoke of 101.6 x 82.6mm respectively, the Strada normally featuring an 11.0:1 compression, Carter four-barrel carburettor and 365bhp at 6200rpm. This was enough for a top speed approaching 160mph and a 0-60 time of just 6.1 seconds putting it firmly in the territory of Ferrari’s new 275 GTB. Customers could alternatively opt for a competition-spec Corsa motor that had its compression dropped down to 10.5:1, this so as to reduce detonation symptoms.
 

Iso A3/C Stradale		 Corsa motors normally got four twin choke Weber 45 DCOE sidedraught carburettors with cross-over ram induction for the fuel-air mixture although some were originally fitted with 42's. Corsa engines also featured polished ports and combustion chambers, high carbon connecting rods, hot camshafts and free flow exhaust systems. All this equated to 405bhp at 6000rpm and enabled the Corsa's to hit 186mph down Le Mans' famous Mulsanne Straight. Acceleration times were also dizzyingly fast with 0-60 possible in around five seconds.
   
To clothe his state of the art machine, Bizzarrini worked with the legendary Giorgetto Giugiaro to create one of the most exotic bodies of the early 1960’s. Fabricated by Piero Drogo’s Sports Cars of Modena, the light alloy bodywork was riveted onto the chassis to form a combined monocoque with the frame. But no two early A3/C's were totally identical, many featuring minor detail alterations from the next. Indeed, while the 1963 prototype (chassis B 0201) and a handful of early production cars featured banks of four louvres behind each front wheelarch, some later examples used twin louvres with decorative horizontal slats, most getting tall single banks that were louvred either vertically or horizontally and again, ahead of each door. Other distinctive features were radiator cooling nostrils carved into the nose. Flanked by covered headlights, Strada versions were fitted with attractive chromium rims. Conspicuous by their absence, neither the A3/C Corsa or Stradale were initially fitted with bumpers although some purely decorative pieces were introduced for the back during early 1965. This was around the same time that Bizzarrini chose to replace the flat rear windscreen for a panoramic unit where glass extended down the sail panels towards the rear wings. The first thirteen A3/C's had instead featured two vents carved into each sail panel for cockpit airflow. Other vents were artistically sculpted from the lightweight aluminium panels behind each rear wheelarch, this to aid brake cooling while the tail featured a pair of circular light pods. Little more than 42-inches high, B 0201's bodywork took over one thousand hours to perfect although at the end of the day, everyone involved in the project must have been suitably proud of their achievement.
 

Iso A3/C Stradale		 Those examples of the A3/C completed to Corsa spec got super lightweight pop-riveted aluminium panels, additional engine and cabin cooling ducts, an externally mounted quick fuel filler cap and sliding Plexiglas side windows. But despite the fact that Rivolta would have undoubtedly expected Bizzarrini to decorate the A3/C with Iso badges, the Tuscan affixed his own Bizzarrini of Livorno emblems to B 0201 and nearly every subsequent A3/C constructed, an issue that would have major implications for the Rivolta – Bizzarrini relationship.
   

The A3/C's rakish cabin was typical of an early sixties Italian GT with Bizzarrini's machine making few concessions to comfort, even in more luxurious Strada trim. A huge transmission tunnel usually upholstered in quilt effect leather-faced padding or ‘skai’ plastic lay between steeply raked bucket seats. Drivers were presented with a three-spoke wood-rimmed steering wheel fronting a flat top dash with water and oil instruments immediately ahead. The speedometer and rev counter were bizarrely located centrally in the cabin while, somewhat expectedly, ventilation was crude and inefficient making driving with the windows up in even slightly sunny weather a chore. The boot housed a spare wheel while additional luggage space was provided by the quilted parcel shelf behind both seats. Customers ordering their A3/C to Strada specification benefitted from more comfortable interior fittings with better insulation and acoustics, more luxurious carpet and door trim, glass wind-down windows and a slightly improved ventilation system. Debuting during October 1963 at the Turin Salon (the A3/L on Bertone's stand and the A3/C on Iso's), B 0201 was finished right at the last minute, its bare aluminium bodywork being shown with a distinctive glossed cork finish achieved by polishing the panels with cork mats on the end of electric drills! Star of the show, press and public reaction were all Iso could have hoped for and shortly afterwards, the decision was made to put both the A3/L and A3/C into production. Prototipo Bizzarrini was established in Livorno to construct and sell the A3/C and race the Corsa, but while Renzo Rivolta had intended for both the A3/L and A3/C to be known as Grifo's, Giotto Bizzarrini had registered the name himself and for his own use.
   

Production began in early 1964 and the earliest customer cars were delivered soon after, one of the first (chassis B 0202) contesting the Sebring 12 Hours in March and making the A3/C's competitive debut. Over the next eighteen months, Corsa's racked up several important results including back-to-back class wins in the 1964 and '65 Le Mans 24 Hour race's, but despite this promise on the track, relations between Renzo Rivolta and Giotto Bizzarrini had broken down. By August 1965, their association was finally terminated after A3/C production had barely reached thirty examples. While marketed at the expense of Iso, Giotto Bizzarrini had supplied nearly all the aforementioned A3/C's with Bizzarrini Livorno badges, this after registering the dual model Grifo designation for himself. Understandably, Rivolta was more than a little disgruntled and the two men split, Rivolta acquiring the rights to the Grifo name for use on his forthcoming A3/L while in return, Bizzarrini was given enough component parts to construct fifty vehicles and the sole rights to build the A3/C under whatever name he desired.