Guide: Can-Am for the Streets - a Historical & Technical Appraisal of the McLaren M6 GT
Background
Bruce McLaren had a long held an ambition to build the ultimate super sports car of its day.
For 1969, McLaren created just such a vehicle - a dual-purpose machine in the mould of Ford’s Mk1 GT40.
The new McLaren M6 GT would be offered as a potential race winner at international level, or as a slightly softened road car with a few creature comforts.
Back in 1966, the FIA had reconfigured their racing regulations; the World Sportscar Championship would now be contested by Group 6 Prototypes (with no engine limit or minimum production requirement) and Group 4 Sports cars (which allowed engines of up to five-litres, but required a production run of 50 cars).
As a result of record speeds set by the unlimited Group 6 Prototypes at the 1967 Le Mans 24 Hours, the FIA announced they would impose a three-litre engine limit from 1968.
Cars like the seven-litre Ford GT40 Mk2 / Mk4, the Ferrari 330 P4 and 412 P and Chaparral’s 2F were made obsolete.
Unfortunately, grid sizes in 1968 were low for both the Group 4 and Group 6 categories. Ferrari, Ford and Chaparral had all quit in protest. Porsche’s three-litre Group 6 Prototypes were left to battle it out with the Gulf-backed Group 4 class Mk1 Ford GT40s run by John Wyer Automotive Engineering.
To stimulate entries for the poorly attended Group 4 Sports class, in mid 1968, the FIA announced that, for the 1969 season, they would slash the Group 4 production requirement from 50 to 25 cars.
The 25-car number was a figure Bruce McLaren felt he could meet with a Coupe version of the Trojan-built McLaren M6. It would use the existing M6 monocoque mated to a closed cockpit body that was suitable for endurance racing.
The McLaren M6 GT would be sold with a choice of engines displacing up to seven-litres. Customers would be offered some potentially monster horsepower ratings.
Ultimately, Bruce McLaren thought a total production run of 250 road and race cars might be possible over a multi-year period.
Development took place at the Trojan works and McLaren’s Colnbrook workshop. For the 1969 season, McLaren were chiefly focused on their own factory-built cars for F1 (M7A) and Group 7 / Can-Am (the M8B).
Meanwhile, Trojan built the 1969 customer cars: the M10B Formula 5000 machine and the M6B Group 7 car for Can-Am.
Trojan had been assembling cars for McLaren since 1964 when the McLaren Elva M1A hit the scene. Trojan (which had owned the Elva car company since 1962) came to an agreement with Bruce McLaren to make customer copies of the M1A and also the M1B that followed.
Thereafter, the relationship with Trojan continued.
The first unclothed M6 GT chassis made its debut appearance at the London Racing Car Show in January 1969 where it was presented alongside the new M8A Group 7 car and a prototype Formula A machine.
Several privateers placed orders for the M6 GT to include Tony Dean, David Prophet, John Woolfe, Sten Axelsson and Techspeed Racing.
Chassis
The M6 GT was based around the same Trojan-built aluminium monocoque used by the M6B Group 7 car. This itself was effectively a copy of the M6A as driven by Denny Hulme in 1967 (which had a longer wheelbase than the equivalent car used by Bruce McLaren that season).
The aluminium alloy chassis panels were bonded and riveted to steel bulkheads.
The M6 GT chassis was also identical to the M12 Group 7 customer car built for 1969. In fact, both M6 GTs built in 1969 / 1970 started life numbered as M12 chassis.
As per the M6B, the M6 GT had a 2375mm wheelbase. A 25 gallon fuel tank was fitted in each sill.
Track dimensions were 1321mm front and rear.
Suspension was via double wishbones with additional twin trailing arms at the rear. Coil sprung dampers and anti-roll bars were fitted. For road use, spring rates were softened slightly.
Ventilated 12-inch diameter brake discs were supplied by Girling as were the 16-3-LA calipers.
McLaren fitted their own centre-lock cast magnesium wheels. These measured 15 x 8.5-inches at the front, 15 x 13.75-inches at the rear and were originally shod with Goodyear tyres.
Engine & Gearbox
The chassis was designed to run a mid longitudinally-mounted small block Chevrolet V8. Ford motors were also to have been an option.
Customers would be able to choose an engine of up to seven-litres in whatever state of tune they desired: from docile and reliable to fully loaded competition trim.
The proposed off-the-shelf street option was to be a Bartz-tuned Chevrolet LT1 (an all-iron 90° overhead valve V8). Displacement was 5735cc thanks to a bore and stroke of 101.6mm and 88.4mm respectively.
With an 11.0:1 compression ratio and four Weber 45 IDA downdraught carburettors, peak output was 370bhp at 5800rpm and 370lb-ft at 4000rpm.
In a racier state of tune, perhaps with the latest fuel-injection system, around 500bhp would have been achievable.
Customers were given a choice of either a ZF 5DS-26 or Hewland LG five-speed transaxle. A twin-plate clutch was employed along with a limited-slip differential.
Bodywork
Bodywork was formed primarily from fibreglass. Light weight bodies would be used for racing. Those cars destined for road use would with come with a higher quality, slightly heavier duty shell.
When it appeared, the low-slung M6 GT was one of the most exciting cars available. The shape was highly reminiscent of an M12 with an extended tail that gave it the look of a Le Mans special.
A full complement of lighting was to be employed. The stacked front light assemblies would be mounted underneath Plexiglas covers. Those at the rear were housed on a body coloured Kamm tail fascia that could be opened up with a number of vents if destined for competition use.
Access to the domed Fastback cockpit was via butterfly doors that tilted forwards.
Intake ducts were carved out from the nose and rear fenders.
To further improve cooling, vents were cut from the upper nose and tops of the front fenders.
Interior
As one would expect from a car with a Group 7 racing car monocoque, the M6 GT’s interior was cramped, difficult to get in and out of and offered poor visibility to the sides and rear.
Even in road trim, with a little extra padding for the seats (and a carpeted transmission tunnel / sills), passenger comfort was clearly an afterthought.
Instrumentation comprised a large speedometer and rev counter flanked to the right by a combined oil pressure / water temperature gauge and a fuel meter. The dials were housed on a basic aluminium binnacle painted black to match the rest of the dash.
For road use, a centrally-mounted gear lever was employed. Those cars ordered for racing would be right-hand drive with a right-hand gear change.
Weight / Performance
McLaren quoted a weight of circa 800kg.
With a 370bhp engine installed, the M6 GT could hit 60mph in 4.2 seconds, 100mph in 8 seconds and run to 180mph. Such figures would have made it the fastest road car of its day.
Production & Competition History
Numerically the first car, chassis M6GT-1 (which would become Bruce McLaren’s personal street car), wasn’t completed until early 1970.
By this time, Trojan had long-since delivered the first customer example: chassis M6GT-2 R.
As its ‘R’ moniker suggested, chassis M6GT-2 R was ordered as a competition car. The buyer was British privateer, David Prophet. The McLaren would replace a Lola T70 Mk3 GT and Ford GT40 Mk1 that Prophet had raced in 1968.
David Prophet had hoped to run his new M6 GT at the Silverstone International Trophy Meeting on March 30th. A host of other prospective M6 GT customers had also filed entries for the event to include Tony Dean (for Denny Hulme), Techspeed Racing (for Chris Craft) and Sten Axelsson. However, delays at the factory and the M6 GT’s failure to secure Group 4 homologation led all these other customers to cancel their orders. Most went on to buy Lolas for 1969 instead.
David Prophet Takes Delivery of M6GT-2 R
M6GT-2 R was delivered to David Prophet in late April of 1969. As it neither met the Group 4 or Group 6 regulations, the car had to run in the Group 7 class (where lightweight Spyder bodies were the norm). It could not therefore compete in the World Sportscar Championship or any other FIA-sanctioned event.
This left Prophet with just a handful of stand-alone events to pursue along with the Special GT Championship in Britain where practically anything was permitted.
1969 Criterium des Nivernais, Magny Cours
Prophet’s first contest with his M6 GT was at Magny Cours for the 70km Criterium des Nivernais on May 1st. The non-championship event was organised for Sports cars and Protoypes including the kind of over three-litre Group 6 cars outlawed by the FIA at the end of 1967.
Prophet qualified sixth behind Paul Hawkins (Lola T70 Mk3B GT), Mike Hailwood (Ferrari 350 Can-Am), David Piper (T70), Barrie Smith (Chevron B8) and Pico Troberg (T70).
Hailwood’s Ferrari won the 25-minute race from Hawkins and Piper.
David Prophet posted a DNF for reasons unknown.
1969 Criterium de Vitesse, Dijon
Three days later, Prophet and M6GT-2 R were in action again. Car and driver attended another French unlimited contest: the 20 lap Criterium de Vitesse at Dijon on May 4th.
Prophet failed to finish again.
Victory went to the Lola T70Mk3B GT of Paul Hawkins. Picko Troberg was second and David Piper rounded out the podium in third (both in T70s).
1969 Norisring 200 mile Trophy
Nearly two months passed before David Prophet raced his McLaren again. The next outing was at one of the biggest stand-alone events of the year: the big money 200 mile Norisring Trophy on June 29th.
The 82 lap race comprised two 41 lap heats in front of a massive crowd; it was open to all sports cars and there was no engine limit.
Prophet qualified 15th on the 20 car grid.
Starting from pole was the works Alfa Tipo 33/3 of Ignazio Giunti followed by Jo Bonnier’s Lola T70 Mk3B GT and Vic Elford in Tony Dean’s Porsche 908/02.
Unfortunately, Prophet’s race ended with another DNF. He retired on lap eight of Heat 1 and did not start Heat 2.
Brian Redman was crowned the winner in Sid Taylor’s Lola T70 Mk3B GT. Vic Elford finished second and Rolf Stommelen took the final podium position in his Porsche Salzburg 908/02.
1969 Hockenheim Solituderennen
Prophet took in another German race two weeks later: the 20 lap Hockenheim Solituderennen on July 13th.
Nino Vaccarella was on pole in his works Alfa Romeo Tipo 33/3 ahead of Ignazio Giunti’s sister car. David Piper started third in his Ferrari 412 P.
Prophet qualified outside of the top six and the unreliable McLaren posted a DNF for the fourth race in succession.
Hans Herrmann ultimately won the race in a David Piper Lola T70 Mk3B GT. Gerhard Koch was second in the BG Racing Team Porsche 908/02 and Vaccarella took third for Alfa Romeo.
1969 Crystal Palace Special GT
Chassis M6GT-2 R made its first appearance on home soil two weeks later when David Prophet entered the car for a round of the British Special GT Championship on August 2nd.
Prophet won the ten lap race from Alistair Cowin’s privateer McLaren Mk3B and Willie Green’s third-placed Chevron B8.
The M6 GT completed the event at an average speed of 89.35mph and also set fastest lap.
1969 International Flugplatzrennen, Wunstorf
Another two-week gap followed before M6GT-2 R made what would be its final outing with its original body in place.
David Prophet headed back to Germany for the international Flugplatzrennen at the Wunstorf airfield circuit on August 17th.
Unfortunately, after victory at Crystal Palace, normal service was resumed and Prophet posted another DNF.
The race saw works Porsche 908s sweep the podium positions. Kurt Ahrens Jr. took the win from Gerhard Koch and Rudi Lins.
After the outing at Wunstorf, Prophet converted M6GT-2 R to full Group 7 M12 specification (complete with new body). In this configuration, he ran it three more times in 1969 (posting three DNFs).
Prophet continued to race the car in 1970 when he had a little more success and picked up a couple of podium finishes.
Bruce McLaren Takes Delivery of M6GT-1
In early 1970, Bruce McLaren finally took delivery of chassis M6GT-1, which was originally conceived as the prototype for a subsequent batch of road-going production M6 GTs. The car had been much delayed; primarily because of McLaren’s 1969 Can-Am and Formula 1 programmes.
Chassis M6GT-1 featured a number of differences compared to David Prophet’s racing variant. In addition to a trimmed cockpit, it came with custom body trim and retractable headlights which had to be manually raised and lowered using finger holes in the leading edge of the light pods. The suspension was softened and a thicker, higher quality fibreglass body was fitted.
Bruce McLaren had chassis M6GT-1 painted red and the interior trimmed in black. Upon completion, it was registered OBH 500H.
M6GT-1 was first seen in public at a reception held by Barry Newman who was the sponsor for Howden Ganley’s McLaren M10B Formula 5000 campaign. Newman was a friend and close neighbour of Bruce McLaren.
Over the next few months, Bruce McLaren used M6GT-1 for his daily commute and to attend race meetings.
Death of Bruce McLaren and End of the M6 GT Programme
Unfortunately, the M6 GT programme was effectively shut down after Bruce McLaren was killed testing the new M8D Group 7 car at Goodwood in June 1970. The M8D’s rear bodywork came adrift at high speed and the car ploughed into a bank at the side of the circuit.
Following Bruce McLaren’s untimely death, M6GT-1 was sold to Phil Kerr and Denny Hulme. Kerr and Hulme had the car exported to New Zealand where it was displayed at the Museum of Transportation and Technology in Auckland.
Trojan subsequently built up one additional M6 GT (chassis GT-1969E, an evaluation car) which went on to star on the cover of the December 1974 cover of Road & Track magazine.
Text copyright: Supercar Nostalgia
Photo copyright: McLaren - https://www.mclaren.com
