Ferrari 308 GT/M – Group B Prototype

Published on: Mar 05, 2018 @ 15:43
(C) RGBS - Dylan Smit
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After the World Rally Championship’s had risen in popularity in the late 1970’s, Ferrari received numerous requests for a Group 4 rally version of the 308 GTB. Not wanting to get directly involved due to its prior commitments in Formula One, Ferrari referred these customers to Michelotto instead. The well-known race engineering firm would devise a Group 4 rally package which was later mildly updated in 1983 to take advantage of the looser Group B regulations. However, behind the scenes the company had a more extreme option in mind.



Ferrari 308 GTB – Group 4

The Ferrari 308 GTB was never used as a factory “works” entry but the company witnessed the Group 4 cars perform well on European and Italian Rally Championship tarmac rallies. This convinced Ferrari to make Michelotto an official partner in the development of a purpose-built Group B contender for 1982. The car was expected to be homologated via use of the revamped evolution (ET) feature of the Group B regulations which demanded 20 examples to be built. Michelotto was thus basically given carte blanche on the car which allowed for extensive modifications from the standard 308.

The 3.0L quattrovalvole V8 engine was mounted transversely beside the gearbox in the standard 308 GTB and Group 4 cars. While this made the car very compact and well balanced, it significantly impeded accessibility to vital mechanical parts. Michelotto opted to mount the engine longitudinally with the gearbox bolted rearwards to make it easier for mechanics to perform the lightning-fast services often necessary between rally stages.

The biggest change for the Group 4/B car was the position of the engine.

An entirely new steel tubular frame was built to accommodate the radical changes. The engine itself was completely overhauled with lightened and strengthened internals, a less restrictive equal length exhaust setup and a customised Bosch/Kugelfischer injection system. The end result was a strong 363 BHP at 8900 rpm, which was directed to the rear-wheels by a Hewland 5-speed manual transmission.

Even though the Audi quattro had already shown the rallying world that four-wheel drive might represent the future, Michelotto and Ferrari, amongst some other manufacturers, relied on tried and true concepts. As such, apart from the longitudinal engine, the prototype followed the same general recipe as the very successful Lancia Stratos.

Ferrari had given Michelotto free reign to raid their parts bin, which resulted in a mixed bag of 308 and even Mondial components used on the rally machine.  The car’s suspension consisted of double wishbones and coil springs on all four corners to ensure stability under all conditions.

Outwardly, the presence of this design philosophy was undeniable; the car had very short front and rear overhangs, which improved weight distribution and enabled the car to change direction instantly, hence creating an incredibly nimble vehicle which would be perfectly at home on tight, twisty rally stages.

The 308 GT/M’s exterior shape took inspiration from the fluid Group 5 512BB/LM.

Visually the new rally weapon bore similarity to the Pininfarina-designed 512BB/LM endurance racer. Pencilled by Boniolo Design, the 308 GT/M was in essence a shrunken down version utilising largely the same aerodynamic principles. Thanks to the exclusive use of carbon fibre composite body panels, the finished machine weighed only 840 kg (1,852 lbs).

Group B regulations divided the category into sub-classes based on displacement, hence the 2927 cc Ferrari would have to take 120 kg worth of ballast to bring it up to minimal 960 kg class weight. However, even with the extra heft, the GT/M would have been the rally car with the best power to weight ratio in its early design period.

The finished car was named 308 GT/M in honour of Michelotto’s hard work, albeit the car is also known as the “308 IMSA” for its quite liberal performance modifications. Unfortunately, progress on the car had been painfully slow due to the chaotic nature of the collaboration between Ferrari and Michelotto engineers. This resulted in the first car not reaching completion until early in 1984.

The GT/M was then sent back to Maranello for a rigorous testing programme at Ferrari’s Fiorano test track. During this time the car was continuously tweaked to find the ideal setup. Different mechanical parts and aerodynamic setups were tried, including various wheel base lengths for stability. The performance was impressive – with a 0-100 kph (0-62 mph) time of under four seconds and a top speed of 270 kph (167 mph).

Although the car proved to be reasonably quick in the tests, Ferrari allegedly started to doubt the GT/M’s potential to compete in the increasing speeds of Group B since it had seen the similarly designed Lancia Rallye 037 get beaten by the mighty four-wheel drive Audi quattro, and soon realised its own prototype no longer stood much chance on loose surfaces. Competing for victories only on tarmac rallies simply wasn’t an option for the famously proud Italians.

Even though the design study had been carried out in complete secrecy, the existence of the 308 GT/M eventually reached the outside world. Not long afterwards, Ferrari received a purchase offer for the prototype from one of his most loyal customers – Belgian racing driver Jean “Beurlys” Blaton.

Blaton had been racing prancing stallions since 1957 and was on good terms with the company’s founder, Enzo Ferrari. Using this good relation to his advantage, he was able to talk Enzo into selling him the car for an undisclosed amount. Blaton then took the car back to Belgium, and sporadically campaigned it in local rally events.

After Blaton’s successful purchase, Italian rally driver Raffaele “Lele” Pinto gave Ferrari a call asking for a GT/M. Pinto had been a factory driver for Fiat and Lancia in the 1970’s, becoming European Rally Champion in 1972 just before the existence of the World Rally Championship’s (WRC) drivers title. Ferrari agreed to build him a car, which Pinto used only once at the 1984 Rally Autodromo di Monza.

As expected the 308 GT/M was seriously quick but Raffaele Pinto would ultimately finish the rally in 4th position behind a “normal” Michelotto 308 GTB driven by Björn Waldegård and 2:40 off the pace of event winner Attilio Bettega in his Lancia Rallye 037. This result is said to have been the final nail in the coffin for Ferrari’s ambitions with the GT/M, hence cancelling the project soon afterwards. Pinto would return the car to Michelotto where it was repaired and subsequently registered for road use.

A third and final car was built using a spare chassis for Dutch Ferrari collector Nico Koel. The car was completed in 1986, but never showed up at the starting line of a rally stage. Instead, Koel enjoyed racing the car at select national and international Ferrari track days. The Dutchman’s car is still in impeccable condition and remains a welcomed guest at Ferrari meetings.

Although Ferrari had abandoned the idea of Group B rally racing, the company wasn’t keen on letting the 308 GT/M project engineering going completely to waste. The lessons learned proved invaluable which eventually lead to the development of the legendary 288 GTO and its “Evoluzione” racing derivative. To this end the relationship between Ferrari and Michelotto would endure.


Group/Class B/12 PROTOTYPE
Design / Production 1981~1986 #built: 3
Type Tipo F115A, V8, DOHC 32v, gas located middle longitudinal, 90 degree V8
Displacement 2927 cc WRC = 2927 cc
Compression ratio 11.4:1
Output power – torque
  • 363 HP @ 8900 rpm
– lb-ft (- Nm) @ – rpm
Materials block: light alloy cylinder head: light alloy
  • Normal / Natural
  • Bosch Kugelfischer mechanical fuel injection
Ignition Magneti-Marelli electronic ignition
Cooling system water-cooled front mounted
Lubrication system dry sump dual front-mounted oil coolers
Type rear-wheel drive Hewland 5-speed manual gearbox
Gearbox ratios N/A N/A
Differential ratios N/A limited slip differential
Clutch hydraulic – Borg & Beck – twin plate
Type steel tubular spaceframe with integrated roll cage, lightweight carbon/Kevlar bodyshell
Front suspension double wishbones, coil springs, anti-roll bar
Rear suspension double wishbones, coil springs, anti-roll bar
Steering system rack and pinion N/A
  • F: ventilated discs
  • R: ventilated discs
dual circuit with servo, pedalbox with adjustable brake-bias
length: – mm (- in) width: – mm (- in) height: – mm (- in)
wheelbase: 2340 mm (92.1 in) front track: 1480 mm (58.3 in) rear track: 1610 mm (63.4 in)
Rims – tires
  • N/A
  • N/A
Dry/Unladen Weight 840 kg (1852 lb)
Weight/power 2.3 kg/HP (5.1 lb/HP)
Fuel tank N/A



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(C) Article by Dylan Smit / RGBS (edited)