Fitted with a V12 with four chain-driven overhead camshafts, the 315 S was a update to the single camshaft engine. In addition to being more powerful, the engine was also twenty pounds lighter and more reliable.
Built as an evolution of the 290 MM that was named after a winning run at the 1956 Mille Miglia, the 315 S was Ferrari’s answer to a horsepower threat from Maserati and their 400 bhp V8.
Development for the 315 concentrated on the engine which used new cylinder heads designed by chief engineer Jano Vittorio. They included his classic twin overhead cam layout – the same he had just applied to Lancia’s V8.
Jano’s design used screwed in tappets which acted directed on the camshaft. With two 12-point Marelli distributors, 48 valves and 24 plugs, this engine the most complicated wade by Ferrari at the time. One major setback was the limited room for the intake manifold which obfuscated a straight intake tract.
With the new cylinder heads that bolted straight onto the 1956 block, power was up to 330 bhp and redline was increased from 6500 to 8000 rpm. These engines grew over the season by increasing to the bore and at the Mille Miglia 390 bhp had been realized with the Type 335 S.
The rest of the car was adopted from the older cars, and the chassis was similar to the 290 MM and 375 Plus with its large oval tubes triangulated by smaller diameter supports. At the rear was a 1956 version of the 5-Speed Transaxle. Brakes were similar to the Lancia D50 Drums with diagonal fins and Alfin linings that were also a Jano design.
The seven race season of the World Sportscar Championship started at Buenes Aires in Argentina at the dangerous Costanetera circuit which was won by the 290 MM car. Sebring was a failure, but the third round at Mille Miglia would be signature.
For the 1957 Mille Miglia, four large Ferraris were present, Piero Taruffi and Wolfgang von Trips each got a Ferrari 315 to themselves joined by a pair 390 bhp 335 S racecars for Peter Collins/Louis Klemantaski and Alfonso de Portago/ Edmond Nelson.
With Jaguar and Aston Martin largely absent as well as a single Maserati 450 S entered, Ferrari seemingly had an easy victory with Piero Taruffi driving number 535 to victory and Wolfgang von Trips right behind, but unfortunately it was a sad day in motor racing history.
Tragedy struck when Alfonso de Portago and Edmond Nelson had a tire blow-out at 200 kph. The results were fatal, killing 12 spectators and the passengers. This event marked the end of the Mille Miglia. After 1957, a more restricted Mille Miglia was staged in 1958, 1959 & 1961, but these were not the all-out road-races like the previous events.
The rest of the season was lackluster for Ferrari, losing Lemans and the Nurburgring to Aston and Jaguar, The final round at Venezuela decided the championship between Ferrari and Maserati, but nearly all the Maseratis dropped out, leaving Ferrari with the championship.
Many of cars still raced, and some in America, past 1957, but due to a three liter engine displacement limit, the Testa Rossa picked up where the 290, 315 and 335 left off.
Our feature 315S, chassis #0684, was the same car Piero Taruffi drove to victory at the 1957 Mille Miglia. It is seen at the 2002 Pebble Concours d’Elegance, where it took first in class after an excellent restoration.