May 31

May 31 Guide: Ferrari Dino 308 GT4 LM

Ferrari - Dino - Ferrari 308 GT4 - 1970s Italian Cars - 1970s Supercars - 1970s Sports Prototypes - 1970s GT Racers - Group 5 1972-1975 - Bertone

Background

By 1974, Ferrari dealers in the USA were struggling. The market for gas guzzlers was in the midst of being ravaged by the OPEC oil crisis while garage inventories typically comprised ageing Dinos and Daytonas which, along with some new old stock GTC/4s, were proving hard to shift.

The situation for American franchisees was arguably worse than in the rest of the world because neither of Ferrari's new 12-cylinder models (the 365 GT4 and 365 GT4 BB) were Federalised for sale in the US.

With these flagship models outlawed on safety and emissions grounds, once Dino 246 production ended in late 1974, the only brand new model American customers could officially go and order was the 308 GT4 which wasn't even badged as a Ferrari.

In an attempt to boost the 308 GT4's credentials, Ferrari's American distributor, Luigi Chinetti, asked the factory to build him a competition version to race at Le Mans in 1974.

Chinetti was no stranger to motor sport; pretty much ever since Ferrari's inception he had been a prolific entrant, initially as a driver and then as the owner of the eponymous North American Racing Team (NART).

While it may have been unusual for Ferrari to build a competition car from a model that was never designed to go racing, Chinetti was no ordinary customer. NART were normally among the first to receive the latest machinery and Ferrari had created special models for Chinetti in the past. Most recently there had been the 1969 365 GTB/4 Competizione Prototipo and the 1972 Dino 246 GT/C, both of which had also been campaigned at Le Mans.

Sympathetic to his American distributor’s plight, Enzo Ferrari agreed to build a 308 GT4 LM once Chinetti had secured the necessary finance. This came from Los Angeles Ferrari collector, Bill Schanbacher, who became the car’s de facto owner.

The relevant racing categories in 1974 were split between Groups 3, 4 and 5.

Group 3 had a production requirement of 1000 units in a twelve month period and only safety modifications were generally permitted.

Group 4 had a 500 car production requirement in a twelve month timeframe. Some performance modifications like wider wheels and tuned engines were allowed but Group 4 cars were still heavily derived from the production models upon which they were based.

Group 5 was for out-and-out Prototypes. There was no minimum production requirement but engines were limited to three-litres.

Because the 308 GT4 had only been unveiled at the Paris Motor Show in October 1973, it fell well short of meeting the homologation requirements for Group 3 and Group 4.

As a consequence, the 308 GT4 LM would have to run in Group 5 alongside machines that were little more than F1 cars with full-width bodies.

Nevertheless, Ferrari agreed that a good showing at Le Mans would generate some useful publicity and boost sales.

Work began on a prototype 308 GT4 (chassis 8020) which was rebuilt from the ground up. A radical weight loss programme was undertaken and the engine was uprated to produce 45bhp more than standard. Massive new spoilers were also fitted.

Chassis

The GT4’s Tipo F106 AL 100 tubular steel chassis was lightened wherever possible. Separate square tube subframes for the engine, suspension and steering were retained while those normally fitted for the bumpers were deleted. As usual, the floors, inner wheelarches and front bulkhead were formed in glassfibre.

Suspension was independent all round via unequal length wishbones, coil springs and Koni shock absorbers. Anti-roll bars were installed front and rear. For the LM, the wishbones were drilled for lightness, solid bushes were fitted, uprated dampers were installed and the anti-roll bars were thickened up.

The standard fuel cells with their combined 80-litre capacity were switched to a single 180-litre gas tank. It was located in the back of the cockpit as opposed to the original layout of up against the rear bulkhead either side of the engine.

Ferrari’s existing twin circuit brake system was adapted to run the master cylinders, linkage box and hoses from the 365 GT4 BB. New four-piston Girling calipers were added along with competition brake pads. The standard GT4’s ATE discs were retained.

The regular Cromodora 14 x 6.5-inch wheels were switched to 15-inch split rim wheels from Campagnolo. The new rims measured 8-inches wide at the front, 10.5-inches wide at the rear and were shod with Goodyear racing tyres.

Engine & Gearbox

In the engine bay was an endurance racing version of the transversely-mounted Tipo F106 AL 90° V8.

As per the standard car, the LM power unit featured belt-driven dual overhead camshafts for each bank of cylinders plus a cast alloy block, cylinder head and sump.

Owing to time constraints, a wet-sump lubrication system was retained, but the oil pan baffles were modified to reduce starvation under hard cornering.

Other upgrades included the pistons and connecting rods from the 365 GTB/4C plus a specially machined crankshaft and cylinders. The cylinder heads were ported and polished, the valves were also polished and racing camshafts were installed. Enormous Weber 42 DCNF carburettors were added along with a racing exhaust system.

All told, the LM engine pumped out 300bhp at 8200rpm. This compared to 255bhp at 7700rpm for the standard motor.

Transmission was via the regular five-speed gearbox (albeit equipped with new ratios), a single dry-plate clutch and limited slip differential. As usual, the gearbox was mounted in unit with the engine, below and to the rear of the sump.

Bodywork

Much of the LM’s weight reduction was related to its heavily-modified bodywork.

Steel panels were routinely switched to aluminium or fibreglass and all the glass, bar the windscreen, was exchanged for Plexiglas.

The front bodywork lacked the retractable headlights used on the original. The front bumper and apron were deleted to accommodate fixed headlights mounted under clear plastic covers. There was also a gaping radiator intake. A new wraparound chin spoiler was added which merged with the flared front fenders.

Underneath the aluminium front lid, much was reconfigured; bigger radiators were installed and ducts fed cool air into the cockpit.

The doors were also formed in lightweight aluminium as was the single piece engine cover that had a variety of custom louvres.

At the back, a huge adjustable spoiler was faired into the rear wings. It was mounted on tubular pylons bolted to the tail fascia which itself was now equipped with a meshed grille between the lights. Three further grilles were cut from the rear apron and spanned almost the full width of the car.

The rear fenders were dramatically flared and incorporated large brake cooling ducts. Bertone’s distinctive boomerang intakes located on each sail panel were also opened up. Recessed quick fuel filler caps were mounted just behind the doors on both sides.

Other modifications included ID lights, pin-fasteners, a high-speed single wiper and extra spot lights.

Interior

Inside, Ferrari fitted a roll cage, fire system, racing seats and harnesses. The rear seats were junked to make space for the new long-range fuel tank. Blue fabric was used to trim the bucket seats, the sidewalls and the lightweight door panels.

The standard dash and steering wheel were retained but the original centre console was removed.

Weight / Performance

At 1065kg, the LM was 200kg lighter than the standard 308 GT4. Top speed went from 155mph to 176mph.

Completion & Testing

Chassis 8020's conversion to LM trim was completed early June of 1974. This was just a couple of weeks before it was set to debut at the Le Mans 24 Hours.

The car underwent a series of tests at Fiorano, during which time it was predominantly painted red.

By the time 8020 arrived at la Sarthe, its roof, engine cover and spoilers had been repainted white and NART's signature blue and white centre stripe had been added.

1974 Le Mans 24 Hours

Le Mans was round five of the 1974 World Sportscar Championship and chassis 8020 was entered for Giancarlo Gagliardi and Jean-Louis Lafosse to drive. They qualified 38th which would have been good enough for 16th of the 21 GT cars present.

However, as a Group 5 entry, the GT4 would technically be up against the likes of Matra's MS670C and the Mirage GR7 plus NART's old Ferrari 312 P that had been reconfigured in the style of a 312 PB.

Also among the five-car NART entry were a trio of 365 GTB/4Cs, two of which were factory-built Series 3 variants while the other was an aftermarket conversion. The 365s were entered in the GT class against opposition from Chevrolet (Corvette), De Tomaso (Pantera) and Porsche (911 3.0 Carrera RSR).

Unfortunately, after four hours and 30 laps of the 8.5-mile circuit, clutch failure forced the GT4 LM into retirement.

To the crowd’s delight, the race was won by Henri Pescarolo and Gerard Larrousse in their Matra MS670C. The GT class fell to Cyril Grandet and Dominique Bardini in the Shark Racing Ferrari 365 GTB/4C that placed fifth overall.

One of the NART GTB/4Cs was sixth overall (second in class) and the team’s 312 P was ninth (sixth in class). Another of Chinetti’s 365 GTB/4Cs also placed eleventh overall (fifth in class).

1975 Le Mans 24 Hours

Chassis 8020 was set to appear at the next year’s event as well although, as a result of political wrangling, the 1975 Le Mans race was a stand-alone event and not part of the World Sportscar Championship.

NART were back with a typically eclectic four-car entry that also comprised an old 365 GTB4/C, a lightly modified 365 GT4 BB they had prepared in-house and a 365 GTB/4 that had been rebodied as a targa-topped Spider by Michelotti.

All the NART entries had pre-qualified during the week-long build up to the race.

In the GT4 LM, Giancarlo Gagliardi and Harley Cluxton had posted a time comfortably quick enough for them to start the race. However, after initially approving chassis 8020 to run, a couple of days later, the ACO did a U-turn and disqualified it on the grounds it was not sufficiently fast enough compared to the Sports cars it was grouped with.

NART's dispute with the governing body was still going on by race day.

With seemingly no chance of the 308 being permitted to run, Chinetti decided to withdraw his three remaining Ferraris barely an hour before the start.

What made the ACO's stance particularly inexplicable was that they had organised separate classes for all manner of GT cars including a GTX group for un-homologated machinery.