Great interest has been shown in some of the cars used for the series of races held recently in the Argentine, when the temporary existence of a “Formula Libre” gave people a chance to experiment. Ferrari was quick to take advantage of this and, together with the standardisation among his cars, he soon concocted some rather desirable “Argentine Specials.” Using existing components, he built five cars altogether. Three of them used the new Formula I chassis that made its debut at Monza last September. These new chassis are 11 cm. longer than the original G.P. cars and are naturally slightly heavier. Into these chassis were fitted Formula II engines, being the unblown 2-litre V12-cylinders, but for this occasion a single-stage supercharger was fitted, as used on the original Formula I cars, The other two cars for the Argentine used the same power units, but these were fitted into the short Formula I-type chassis, similar to that used by Whitehead.
These single-stage supercharged 2-litres give 290-303 b.h.p. at 6,500 r.p.m., and the complete cars weigh 11 cwt. 44 lb. for the short chassis, and 12 cwt. 20 lb. for the long-chassis models. This difference in weight is accounted for mainly by the longer frames, and the improved brakes, plus all the little bits of extra weight that inevitably go with an increase in wheelbase. There appears to be a great advantage to be gained by keeping a high degree of inter-changeability among one’s various models.
Maserati were not so fortunate, for their 2-litre car bears no resemblance to the Formula I model, and they were unable to make any use of the larger engine. Not to be outdone, however, they increased the stroke of the 4 CLT/48 cars, from 78 mm. to 90 mm. by fitting new crankshafts, thus bringing the capacity up to 1,720 c.c., giving an increase in power from 245 b.h.p. at 7,000 r.p.m., to 280 b.h.p. at 6,400 r.p.m., and even more surprising is the figure of 200 b.h.p. at 4,000 r.p.m. for this engine. In all other respects the cars were standard, but one new model was built, which had a chassis frame of lighter gauge tubes, a lighter oil tank and an aluminium fuel tank, lighter than before, as well as softer suspension, the saving in weight being very nearly 50 lb.
The Scuderia Milan, not having completed their new chassis in time, sent a standard Milan model, one of those built for the last Monza meeting. Having the same bore and stroke as the 4 CLT Maserati, and running at the same r.p.m. of 7,000, the Mario Speluzzi-designed Milan engine is claimed to give 320 b.h.p., using nearly 40 lb./sq. in. boost pressure, against the Maseratis 32 lb./sq. in. It is interesting to note, that the power absorbed by the Milan two-stage Roots supercharger layout is 62 b.h.p., while the Maserati layout absorbs 50 b.h.p.
The Type 158 Alfa-Romeo is its 1948 condition still heads the field with a power output of 330 b.h.p. at 8,200 r.p.m.