In the over-2-litre class the issue lay between Ferrari and Maserati, and the Maranello firm entered two 12-cylinder 3 1/2-litres as used in the Giro Sicilia, to be driven by Castellotti and Fangio, and two four-cylinder 3 1/2-litres, similar to the Sicily-winning car, to be driven by Musso and Collins. There were no radical changes to them, and only Collins carried a passenger, the others having the left side of the cockpit covered and a single wrap-round screen.
From Maserati came three works entries, Perdisa and Taruffi with 3-litres as raced in Argentina and Sebring, the only modifications being the fitting of enormous fuel tanks in the passenger seat, and one new 3 1/2-litre Maserati started, in the hands of Moss, it being a brand new car both in design and construction. The engine of 86 by 100 mm. bore and stroke was 3,485 c.c. and while still a six-cylinder was not an enlarged 3-litre, but an entirely new design as far as castings, portings and so on were concerned. Unlike the 3-litre, this new engine had the carburetters mounted horizontally and not slightly downdraught, while the magnetos were mounted on the rear of the camshafts. On the back of the clutch was a step-down pair of gears not only lowering the prop.-shaft line but also reducing the speed of the shaft. This drove to a new unit-construction gearbox/differential unit, containing five speeds, all of which could be used. The gearbox part of the final drive unit was in front of the axle line, whereas the 3-litre and G.P. cars have the gearbox on the side of the differential. With the new layout the de Dion tube had to pass behind instead of in front of the final drive and a vast improvement was made by locating the central guide of the tube directly to the rear cross-member instead of on to the final-drive casting. The new frame was of the space type, using fairly large diameter tubing as on the 3-litre and G.P. cars but was of a different formation. The rear suspension still used a transverse leaf-spring, mounted high above the rear end, but the de Dion tube location was on an extension below the tube itself. At the front the well-tried double wishbone and coil-spring layout was retained, but both front and rear were fitted with telescopic shock-absorbers in addition to the normal vane-type Houdaille. New front brakes as large as those on the G.P. cars were fitted and 3-litre-type rear brakes. A great deal of thought had gone into the layout of the rear suspension and the construction, and the whole car was rather heavy as it was intended for a bigger engine than 3 1/2 litres, which has yet to be finished. In the tail of the car was a 40-gallon fuel tank and the oil tank, while on the left of the cockpit was another fuel tank of 18 gallons. As on the 3-litre, the steering was right-hand drive, the column feeling its way between the three double-choke Weber carburetters by means of universal joints. This new 3 1/2-litre engine was claimed to give over 270 b.h.p. at 5,800 r.p.m. and to be possessed of excellent torque characteristics.
Among the private owners in this class were Bordoni and Gerini with normal 3-litre Maserati, Heath with the H.W.M.-.Jaguar, Graham with an XK120 Jaguar, and some early privately-owned Ferraris.
The 1,500-c.c. to 2,000-c.c. class of sports cars was almost a Maserati benefit, there being six-cylinder MG models driven by good drivers, bad drivers and indifferent drivers, among the first group being Scarlatti, Giardini and Pucci, while Bellucci had one of the new 150S models fitted with a 2-litre four-cylinder engine, this differing outwardly from the 1 1/2-litre four-cylinder only in having larger-choke carburetters which were mounted at a slight downward angle. Against these were some 2-litre Ferraris, both four-cylinder and 12-cylinder, the only serious opposition being the new four-cylinder of Sbraci, this being a small version of the Monza Ferrari to look at but having a non-de Dion rear end, suspended on 1/2-elliptic springs.
The 1,100-c.c. to 1,500-c.c. group was more interesting, having factory entries from Maserati, Alfa-Romeo, Osca and Porsche. Behra was in a 150S Maserati, virtually as sold to the public, but with a few detail modifications and quite a bit more power; Sanesi was driving a hotted-up Alfa-Romeo Giulietta Spyder open two-seater; the Osca team was as raced in Sicily, being Villoresi, Maglioli and Cabianca; and there were two Porsche cars from the factory. As Frankenberg was not able to be in Italy his entry was taken by Bracco, the car being one of the 1955 Spyder models, but the other was a brand new car making its first appearance and driven by Herrmann. This had a small-diameter tube space-frame and aluminium body, the rear no longer hinging upwards about the extreme end, but having hinged panels on each side for getting at the carburetters and the air grilles on the top of the tail hinged for access to the rear-axle details. Any major work necessitated unbolting the whole tail of the car from the cockpit rearwards. Front suspension and brakes were unchanged but the engine was much modified and fitted with a five-speed gearbox but not with the low-pivot swing-axle that Porsche have been experimenting with. In addition to these works entries there were privately-owned 150S Maseratis driven by Cornet, Bourillot, de Tomaso, Petralla and Michel. All these were the standard models, rather solidly made and heavy in the chassis by English standards, but Maserati pointed out that the chassis was designed to take a 2-litre engine and still not break up over 1,000 miles of Italian roads, including the rough mountain passes. The chassis frame on these cars is built up from fairly large oval-section tubing and small round-section tubing to form a peculiar structure that is neither “ladder-type ” nor space-frame, but a complicated mixture of the two. The front suspension is by wishbones and coil-springs, but there is no normal kingpin as on the Grand Prix cars. The point of each wishbone forms a pivot for rotational and up-and-down movement, and into this fits a very short kingpin, one top and one bottom, and these are part of the stub-axle forging. The rear suspension is de Dion with a transverse leaf-spring mounted low beneath the whole assembly, with the tube located centrally on a sliding joint, the attachment to the tube being on a bracket welded below the tube itself, to give a lower roll centre. The four-cylinder engine remains unchanged from the prototype which appeared at Nurburgring last year, having two double-choke Weber carburetters, eight plugs and two overhead camshafts. The four-speed gearbox bolts onto the rear of the engine and an open propeller-shaft drives to the differential unit mounted on the rear of the chassis frame. Right-hand steering is utilised and a full-width aluminium body, and with only the driver in place the left side of the cockpit is covered by a metal panel and a wrap-round windscreen is used.
The sports class, from 750 c.c. to 1,100 c.c., is the home of amateur-built “specials,” early 1,100-c.c. Oscas and privately-owned models from the small firms like Stanguellini and Ermini.
In the 750-c.c. class there was some factory support in the shape of two very beautiful little 750-c.c. Osca four-cylinders with twin overhead camshafts, being scaled-down versions of the factory cars; these being driven by Chiron and Capelli. Against these were Le Mans-type D.B. and Panhards, and special Renaults from France, Stanguellinis, Giaurs, etc.
There was one more open sports class, seemingly specially designed to allow the British to win something, and it was for open cars costing not more than 2 million lire (£1,150 approximately) and of catalogue specification. This attracted two works M.G. MGA models driven by Nancy Mitchell and Scott-Russell, another Italian-entered one, a Porsche Speedster, Triumph TR2, A.C. Ace, Jaguars and Austin-Healey 100S models, and a lone Spyder Fiat 1,100.
In the over-2-litre Gran Turismo class Ferrari entered a factory car driven by Gendebien, this being a 12-cylinder 3-litre, of which over 100 have now been made, with wishbone and coil-spring i.f.s. and 1/2-elliptic-sprung normal rear axle, and a very solid “vintage-like” chassis. It was fitted with a small coupe body by Scaglietti, coachbuilder in Modena. There were some private models of this type entered, but the real opposition came from Mercedes-Benz with 300SL models. Private owners were Siedel, Zampiero, Busch, Metternich, Pollet, Mascaranhas, Cacciari and Bongiasca, all receiving attention and advice from the factory, represented by Neubauer and Kling, and a handful of mechanics. In spite of their announcement in the contrary there were two factory cars entered, driven by Riess and Graf von Trips. These still had to be to catalogue specification, but were nevertheless full factory entries. The competition springs and shock-absorbers were available to drivers as well as the private owners, but Trips decided he preferred the standard soft springing controlled by competition shock-absorbers. Mixed in with this class was a group of cars entitled Special Series Touring and this included three special Mercedes-Benz 220a models, stripped of unnecessary weight and having twin-carburetter engines, special camshafts and so on, and were driven by Gunzler, Retter and Bauer, all three being factory sponsored.
This grouping of Gran Turismo and Special Series Touring applied for all capacities, the 1,600-c.c. to 2,000-c.c. class containing the limited-production A6G coupe Maserati models, Alfa-Romeo Sprints, Fiat 8V and the hotted-up versions of 1,900 Alfa-Romeo, and Fiat 1,900. The 1,300.c.c. to 1,600-c.c. group saw Porsche Carreras, the two valiant Sunbeam Rapiers, one driven by Sheila van Damm and Harper, and an M.G. Magnate driven by Grant. The 1,100-c.c. to 1.300-c.c. group contained an enormous collection of Alfa-Romeo Giulietta Sprints and the new Sprint-Veloce version, this being outwardly the same, but having aluminium doors, bonnet and boot lid, Perspex sliding windows, normal floor-mounted gear-lever, twin double-choke Weber carburetters, different camshaft and compression ratio and an ability to rev. to 7,000 r.p.m. It was a very serious attempt to beat the 1,300 Porsche Supers, of which only a few were entered this year. The 750-c.c. to 1,100-c.c. group was subdivided at 1,000c.c. so that, the upper group was entirely Fiat 1,100 with the exception of one poor little Lancia Appia, and the lower class saw D.K.W., Renault, D.B. and Panhard meeting. There were five of the new Renault Dauphines, those of Trintignant, Rosier, Frere and Gilberte Thirion being special factory models with highly-tuned engines. In the up-to-750-c.c. class there were Panhard, Renault, Fiat, Moretti and Abarth, the last-named being special modifications of Fiat 600. Outwardly they were unchanged but the engine had an increased bore and stroke to bring it up to 750-c.c., new crankshaft, camshaft, larger carburetter, improved manifolding, and about the performance of a normal Fiat 1,100 TV.