Profile: Ferrari 312PB

Compact, light and powerful, Maranello’s 3-litre sports car collected race wins and captured hearts around Europe. This example was crucial to the model’s success
Words: Gordon Cruickshank. Photography: Alex P

It’s the height that hits you. At the track, among its rivals from the Seventies, it’s not so obvious. But in the studio, floodlit against bare walls, even with its 12-cylinder yowl silenced, this knee-high wedge of Maranello artistry is redolent of Enzo Ferrari’s unending compulsion to win.

Ferrari’s 312PB fought the sports car championship for three seasons, and dominated it for one glorious year before Matra stole its crown. The chassis featured here was central to that title – an early prototype, it served as the development car and single-handedly carried Maranello’s shield into battle for much of the 1971 season, driven by Clay Regazzoni and Jacky Ickx. The only PB to remain in original short-wheelbase form, its gorgeous noise is still to be heard on race tracks around Europe and America.

First, the name. Ferrari always listed it as plain 312P – 3-litre 12-cylinder prototipo – but to differentiate it from the earlier V12 cars the press soon added B for its boxer (flat) engine. For simplicity we’ll use the PB label here. Curbing sports cars to three litres went back to 1968, but the rulemakers left a 25-car loophole which Porsche rammed the 917 through, smartly followed by Ferrari with the 512S. Though the FIA reacted relatively quickly, the two 5-litre monsters still had a couple of years to blitz the races until a new regulation banned them from 1972.

If it was the death sentence for the magnificent 917, it also meant that the 512 was heading for euthanasia, but in the way of great dynasties there was an heir in prospect. The compact, pretty and punchy 312PB, the twinkle in designer Mauro Forghieri’s eye, had begun its birth pangs. An increase in minimum weight for prototypes to 650kg made Porsche’s 908 an uncompetitive prospect for the 3-litre era, as it relied on light weight rather than high power for its speed, and rather than develop a new engine, Porsche announced it would withdraw from prototype racing after 1971. That confirmed Ferrari’s resolve, and Forghieri took the bold decision to develop the new car by running it throughout ’71 against the 917; meanwhile the brutal 512 would receive no more works development, but in its last valid year would be left to the privateers.

Unlike Porsche, Forghieri already had a strong 3-litre engine, the new flat-12, introduced in F1 in 1970. Theoretically you can’t run an F1 engine in a sportscar, at least not without detuning it substantially. But Ferrari’s unique set up, the recent injection of cash from Fiat’s partial buyout, and the Old Man’s drive for success in all spheres allowed it to spend whatever time and money were necessary to turn its F1 engine into an enduro unit.

Forghieri’s central aim in flattening the iconic V to a boxer flat-12 was to lower the centre of gravity and offer clean airflow to the F1 car’s rear wing. With its four chain-driven overhead camshafts, the 48-valve unit was relatively wide but short, aided by using only four main bearings, which also reduced friction. By the time it went into the sports car the engine had upgraded to a bigger bore, shorter stroke spec with large valves, offering more power and revs. Also the Lucas injection fuel metering unit had moved from the side to the top of the block to improve access, crucial in endurance races. Screwing back the F1 tune by some 40 horses left the PB with about 440bhp, with the red line arriving almost two grand earlier than the GP car at 10,800rpm.

This refined power source sat in, or rather hung from, an ally-clad spaceframe with an extension over the engine to share the suspension loads. On each side of the cockpit were wide sponsons; a main fuel tank filled the left one to counterbalance the driver, with a smaller reserve on the right. Unusually there was a sight gauge for the oil set into one sill. Large surface ducts scooped air to vertical radiators ahead of the rear wheels with the oil cooler crouching on the clutch housing.

If there was a snag in the boxer layout it was that the heads, the rear suspension, and the underslung exhaust pipes all wanted to share the same space, so the sports car copied the F1 rear suspension, with reversed lower wishbone locating on the five-speed gearbox, single top link and twin radius arms. Up front the usual double wishbones sufficed, with the steering rack mounted above the driver’s knees. With these commonalities it was inevitable that the PB was labelled a ‘two-seater grand prix car’ – which didn’t do Maranello’s image any harm at all. To clothe its new machine, Ferrari abandoned the lovely curves of the 312P for a minimal hard-edged, slab-sided form which, with its cutaway tail kick-up, still has a chunky appeal. And thanks to magnesium suspension components it came in under the new weight limit.

By the end of 1970 the new car was lapping Modena in similar time to the 312B2 grand prix car. Things looked good as the factory prepared its two chassis for battle. Only one of them would survive the season – the car profiled here. In January’s Buenos Aires 1000km, Ignazio Giunti, driving 0882, slammed into a stationary Matra and was killed. It was little compensation that the PB had been challenging 917s and 512s for the lead. The wrecked car was not rebuilt, and for much of the ’71 season Ferrari had this car as its sole flag-bearer. Strictly speaking it had two chassis numbers: this car began the season as 0878, but during the year it was involved in a series of accidents; before the final race, the gruelling Kyalami 9 Hours, the factory rebuilt it and renumbered it as 0880, the number it has worn since.

It was a frustrating season, that first one. Repeatedly the 312, looking tiny alongside its 5-litre rivals, nipped at their heels like a terrier hassling a Labrador, sometimes lapping fastest, sometimes grabbing pole, making fewer pitstops thanks to its lighter thirst. But constantly there was a breakage, or an accident; Clay Regazzoni’s spectacular fight back in the BOAC 1000km at Brands Hatch after tripping over a spinner, grabbing a stupendous second place, was a rare highlight. In successive races, Monza and Spa 1000km, 0878 crashed, and while Jacky Ickx and Regazzoni were running away with the Nürburgring 1000km a cylinder seal failed. At the Osterreichring in June the diminutive 312 faced the 917 for the last time, but during a spectacular battle with Pedro Rodríguez in the Porsche, Regazzoni crashed again. At Watkins Glen, with Mario Andretti aboard, a possible win evaporated when the car wouldn’t restart, but 0878 did grab a one-heat win at the non-title Monza 500km. It was at this point the chassis number changed, and with it the team’s luck.

Backed up by a new car, 0884, for Andretti and Ickx, Clay and Brian Redman in 0880 took a commanding win in the Kyalami 9 Hours, their team-mates finishing second after a blistering full-pressure drive to overcome fuel pump problems. While that didn’t affect Porsche’s title, it was a signpost to future greatness.

Six new cars, now with inboard rear brakes, showed that Ferrari was serious about the 1972 championship, with a three-car entry for all 11 rounds and a rich stable of drivers, including Ronnie Peterson. Each driver pairing would alternate between two cars, a luxurious way to go motor racing. Fiat’s millions were trickling through…

Alfa had garnered two wins and good placings with its V8, but its flat-12 engine was again delayed making it an unknown factor. Matra’s MS670 was getting quicker and quicker, but the French were only contesting Le Mans, so the opposition was frankly not strong. However, the boxer was into its stride: a 1-2 at Buenos Aires opened a brilliant season in which Ferrari won 10 out of 11 rounds; the exception was Le Mans. Fearing for its grand prix motor over 24 hours, Maranello stayed at home that weekend and watched Matra finally achieve its longed-for victory. The title, though, was Ferrari’s, by a huge margin, capped by a stunning 1,2,3,4 in the Osterreichring 1000km and winning the Targa Florio, quite an achievement for a two-seat grand prix car. The Sicilian epic, incidentally, gave the hard-used 0880, pensioned off from racing, its last works outing: eventual winners Sandro Munari and Arturo Merzario used it as practice car, fitted with the latest bodystyle and a spare wheel.

For 1973, with the rapid Matras ready to contend the whole series, Ferrari lengthened the PB chassis by 120mm, widened the front track, squeezed 470bhp out and raised the rev limit to a screaming 11,500. But the MS670 was a superb car, while the Ferraris struggled with understeer all season. Impressively, two Ferraris finished at Le Mans, but behind a Matra, and while the title fight stayed open right to the end, it didn’t fall Maranello’s way. With five French wins to only two Italian, the title had blue and white all over it.

Ferrari knew that the PB would need serious revision to face up to the French blue missiles in 1974. But its F1 season had been catastrophic; Ickx baled out, and new man Niki Lauda, backed by Luca di Montezemolo, insisted the team could not fight both battles. Ferrari announced its withdrawal from sportscar racing, and the little 312PBs were retired.

They had accomplished more than the fabled 512; they had thrilled the spectators and charmed their drivers with their light gearchange and that delicious engine which just revved and revved. There have been privateer Ferrari sportscars since, often with quiet works assistance, but the factory never again entered a sportscar in a race. The squat, chunky 312PB was Maranello’s last two-seat warrior.

Race record, Ferrari 312PB, chassis no. 0878/0880

As 0878 – 1971

Sebring 12Hr: Ickx/Andretti – DNF
Brands 1000km: Ickx/Regazzoni – 2nd
Monza 1000km: Ickx/Regazzoni – DNF
Spa 1000km: Ickx/Regazzoni – DNF
N’ring 1000km: Ickx/Regazzoni – DNF
Zeltweg 1000km: Ickx/Regazzoni – DNF
Watkins Glen 6Hr: Ickz/Andretti – DNF
Imola 500km: Regazzoni – 1st Heat 1, DNF final

Renumbered 0880 - 1971

Kyalami 9Hr: Regazzoni/Redman – 1st

Renumbered 0880 - 1972

Targa Florio: Merzario/Munari – practice car

From Maranello 0880 went to Albert Obrist, then passed to Bernie Ecclestone. It was briefly owned by a Japanese collector before US racer Bill Binnie bought it in 2000. After recommissioning by Paul Lanzante, Binnie raced it for two seasons in the Shell Ferrari-Maserati Historic Challenge, winning 10 races. This summer it was bought at Coys auction by Ernie Prisbe who will race it in the USA

Tech spec – Ferrari 312PB

Front suspension:
double wishbones with outboard coil dampers
Rear suspension: single top link, reversed lower wishbones (twin parallel links for ’73), twin radius rods
Wheelrim width: 10in front, 16in rear
Tyres: ’71-2, Firestone; ’73, Goodyear
Brakes: outboard discs front and rear (rears inboard from ’72)
Steering: rack and pinion

Flat 12
Valvegear: dohc, 48 valves
Bore x stroke: 80mm x 49.6mm
Capacity: 2991cc
Fuelling: Lucas injection
Ignition: Magneti Marelli
Maximum power: 440-480bhp
Maximum revs: 11,500

Ferrari, five-speed, variable drop gears from ’72
Clutch: Borg and Beck, triple disc

’71, 2220mm; ’72-3, 2340mm
Front track: ’71, 1425mm, ’73, 1426mm
Rear track: ’71, 1400mm; ’73, 1486mm
Length: 3500mm