The Canadian-American Challenge Cup series has entered its third season with every indication of continuing the enormous success it achieved in its first two years. The series consists of six races, run off in 10 weeks, with the big-bore Group 7 cars chasing some of the largest prizes in the history of road racing. There had been a rudimentary series of professional sports-car races in North America every autumn since the late 1950s, but it was not until 1966 that the Sports Car Club of America and the Canadian Automobile Sport Club brought the organisers together, fashioned a common set of rules and regulations and established an overall series championship.
It was a hit from the beginning, for in each of the first two years new attendance records were set at four of the six tracks and new qualifying and lap records at all six. Indeed, it is somewhat ironic that at the same time as the F.I.A. was busy emasculating such things as the World Manufacturers’ Championship, the S.C.C.A. and the C.A.S.C. was making a success out of the very things the F.I.A. seems to abhor—the big, colourful, unlimited displacement sports/racing cars that thunder down the straights at close to 200 m.p.h. But behind all the noise and excitement the real key to the growth of the Can-Am series has unquestionably been money, spelt $ $ $ $ $ $, and in large quantities. This year the purses for the six races range from a low of £10,000 to a high of £20,000, and the total has been increased by £4,200 to over £93,000. The overall Championship Fund, paying down to 10th place and determined by the usual 9-6-4-3-2-1 scoring system, has been raised 40% to £52,500. This includes £6,250 from each race organiser and £15,000 from the Johnson Wax Co., the sponsors of the series. In addition, the accessory firms have posted more than £73,000 in contingency awards, to push the grand total over £218,000. Even allowing for the fact that only half the contingency awards will be paid out (one can’t collect from both Firestone and Goodyear at the same time), the total actually received by the competitors will exceed £180,000 for the series, or £30,000 for each race.
There are undoubtedly some who will decry this as crass commercialism and an unhealthy influence, but there is no getting away from the fact that motor racing is and always has been an expensive sport, whether it was financed by the private fortunes of wealthy amateurs, the commercial coffers of the petrol companies or the public funds of the Third Reich. The only difference is that these funds were paid quietly under the table, often before the cars had even set foot on the track, whereas in the Can-Am series the drivers have to go out and race for everything they earn. The American system discourages “starting money specials”, puts a premium on good cars and drivers, and has certainly provided North American spectators with some of the finest racing available anywhere.
The first race in this year’s series was held on the very attractive Road America course in Elkhart Lake, Wisc., but the demands of Formula One in Europe and the U.S.R.R.C. and Trans-Am series in the States left everyone short of preparation time. A couple of entrants—Dan Gurney and John Surtees—didn’t make it at all, Jim Hall had to revert to last year’s car at the last moment, and even the McLaren team had to scramble when their usually extensive testing programme was curtailed by the dreadful weather. Nevertheless, after winning five of the six races last year, finishing first and second in the Championship and improving Britain’s balance of payments by £68,000, Bruce McLaren and Denny Hulme had the newest of the new cars.
Just as McLaren’s M7A Formula One car incorporated several features developed in last year’s M6A sports car, so does the new sports car, the M8A, include techniques proven in the Formula One car. The M8A has a pontoon-type chassis fabricated largely in aluminium, with magnesium used in the floor pan and side sills. The fuel pontoons themselves extend to the rear wheels, but like the Formula One car the centre section of the chassis ends at a steel bulkhead behind the seats. The engine is then bolted to this bulkhead via a magnesium plate and becomes a structural extension of the chassis. A pair of triangulated steel tubes running from the back of the engine to the seat-back bulkhead provide further bracing. The rear suspension is attached to a steel bridge across the top of the 4-speed Hewland trans-axle and to a magnesium plate underneath it. Quite apart from the weight saving and greater accessibility, the two major advantages of not having a normal rear chassis to get in the way are that the entire engine now sits four inches lower-with obvious benefits to the centre of gravity-and the rear radius arms are positioned exactly where they are needed (on last year’s car the lower radius arms had to be anchored to the sides of the engine block).
The suspension follows standard practice, but McLaren is alone in using 4-piston Lockheed calipers (as on his Formula One car) acting on 12 x 1.1-in. ventilated discs. The 12-in. wide rear tyres that first appeared in last year’s Can-Am have grown even wider and the suspension has been modified to accept them. Both Goodyear and Firestone now have rear tyres that put a full 15 in. of rubber on the ground, and they expect to bring out 16- or even 17-in. wide tyres before the series is over. These tyres, of course, require new wheels, and McLaren has abandoned castings in favour of an interesting split-rim monocoque design fabricated from wrought aluminium plate. Partly because of these massive wheels and tyres the M8A is not a small car. Although the lower engine permits a 3 in. lower tail, the car is 4 in. wider than the M6A and the 94-in. wheelbase is 4 in. longer.
After McLaren’s great success last year with the M6A it is hardly surprising that several of his more serious competitors are now driving the M6B production versions of that car. Among them are Mark Donohue, Lothar Motschenbacher, Peter Revson, Jo Bonnier and Jerry Hansen. Donohue’s car is actually closer to an M6A½ since it was built up from a spare works chassis acquired by Roger Penske at the same time as he bought McLaren’s works car after last year’s series. The ex-works car, used by Donohue to win the U.S. road-racing championship for the second year in a row, was sold to Hansen. While building up the spare chassis Penske’s team took the opportunity to lighten it by replacing some of the aluminium with magnesium or titanium. They pared off more pounds by moulding a completely new body in a special, very thin plastic to which Penske has exclusive rights.
While McLaren’s new M8As were getting bigger and more radical, his major rival as a constructor was going in the opposite direction. Eric Broadley’s new T160 Lola replaces the highly successful T70, of which more than 100 were sold. Although the wheelbase of the new car is unchanged at 94 in., it is narrower and over 12 in. shorter than the T70. The chassis is again a pontoon-type monocoque made largely in aluminium, but Broadley has gone to great lengths to stress simplicity, efficiency and the maximum use of every panel. As a result, the T160 chassis is easier to manufacture, lighter (95 lb. v. 130 lb.) and stronger than the T70 chassis.
Jim Hall was to have unveiled his new Chaparral 2H but on the Monday before the race it suffered a rear suspension failure and he hurriedly modified last year’s 2G to accept Firestone’s new 15-in. wide tyres. It is typical of Hall’s painstaking approach that he decided to rebuild the 2H’s damaged suspension exactly as it was so he can analyse the failure before rebuilding and/or redesigning. And since Hall shares the Editor’s belief in not talking about a new car until it appears, very little is known about the 2H except that Hall has reverted to a form of fibre-glass reinforced plastic for the chassis and dropped his wing. One new car that did appear was built by Bob McKee, the only American building large Group 7 cars for sale over the past few years. The new McKee has a tubular chassis stiffened by stressed panels and the body is a very pronounced wedge shape, not unlike a much wider Lotus turbine car.
A key feature of all these cars is their use of huge engines, virtually all of them fuel injected. The works McLarens, Donohue, Hall and Chuck Parsons’ Lola T160 are using all-aluminium 7-litre Chevrolets, while Bonnier got his too late to install. Similar 7-litre Chevrolets, but with iron cylinder blocks, are in Hansen’s M6A and the older Mk. 3 McLaren driven by Canadian John Cordts. Over in the Ford camp Peter Revson had a very rare all-aluminium 7-litre in his Shelby-prepared M6B, and Ronnie Bucknum had a similar iron block engine prepared by Holman and Moody in his older Lola T70. Two other interesting Ford engines were the 6.2-litre unit fitted with Gurney-Weslake heads in Motschenbacher’s M6B and a 5-litre version of Ford’s 4.2-litre double-overhead-cam Indianapolis engine installed in George Bignotti’s Lola T70 for Mario Andretti. This is the same car/engine combination driven by Parnelli Jones in the second half of last year’s series. The only engines in the field that didn’t originate from Ford or Chevrolet were a 6.8-litre Oldsmobile in the McKee driven by Charlie Hayes and a 4.2-litre V12 Ferrari in the modified P4 entered for Pedro Rodriguez by the North American Racing Team. The latter car is a spare to the two cars raced by Chris Amon and Jonathan Williams last year.
Bruce McLaren was first on the track for the two days of practice and qualifying but he wasn’t the first to break his own qualifying record of 2 min. 12.6 sec. (108.597 m.p.h.). That honour went to Jim Hall, who showed that despite having last year’s car and not having raced since May he was still a contender behind the wheel. Hall whipped the 2G Chaparral around the 4-mile course in 2 min. 11.4 sec. during an early, untimed session, but when the times counted it was Denny Hulme in the works M8A McLaren who posted the fastest time of 2 min. 11.0 sec. flat. Hall’s best timed run was 2 min. 12.0 sec. and Revson turned 2 min. 13.7 sec. in his McLaren-Ford, but McLaren was having trouble with his soft-compound Goodyear tyres and only managed 2 min. 14.6 sec. before burning a hole in his No. 3 piston (for the second or third time). Andretti, who had turned 2 min. 13.6 sec. during tyre tests, went only three laps before the crank broke in his Lola-Ford, while Donohue’s car didn’t even make it to the track.
Andretti, Hall, Revson and McLaren all changed engines overnight, McLaren seeking to cure the trouble in No. 3 cylinder by going to a slightly richer mixture, a slightly colder plug, and isolating the plug lead from the rest of the ignition harness in case it was picking up a rogue spark. Goodyear came up with a harder compound for the final day of practice and Hulme promptly came up with a scorching lap at 2 min. 9.9 sec. Hall and McLaren improved to 2 min. 11.2 sec. and 2 min. 12.6 sec. but then Donohue really shook things up, first with 2 min. 12.4 sec and then second fastest time of 2 min. 11.0 sec. McLaren and Hall took up the challenge, with Bruce trailing the Chaparral for a few laps before he roared past and usurped the pole position from Hulme with a time of 2 min. 9.8 sec. (110.940 m.p.h.). This also enabled Team Manager Teddy Mayer to ring up the first deposit in the team’s cash register—£650 for fastest and second fastest qualifiers. Moments later Hall pipped Donohue’s 2 min. 11.0 sec. with a 2 min. 10.8 sec., but there was quite a gap to Motschenbacher’s McLaren-Ford and Parsons’ Lola-Chev., both with 2 min. 13.4 sec. Revson didn’t improve on his 2 min. 13.7 sec. in his McLaren-Ford but Andretti got his older Lola-Ford down to 2 min. 13.9 sec. despite the disappearance of 500 r.p.m. at the top end. Hayes’ time of 2 min. 15.2 sec. in the McKee-Olds was unchanged but Rodriguez, his 4.2-litre Ferrari the smallest engine in the field, posted the 10th fastest time with a very creditable 2 min. 15.8 sec. Other possible contenders such as Bucknum, Bonnier and Skip Scot (T70 Lola with 6-litre Chevrolet) were experiencing a variety of engine ills and none showed their real potential.
The next day it drizzled right up to race time and all the wide tyre experimentation went out the window when all but seven of the 29 starters elected to start on narrower rain tyres (Bonnier even conjuring up a set of Formula One Goodyears). As the pace lap for the rolling start began the heavens really opened up, but despite the deluge it was an incident-free start and Denny Hulme splashed into the lead from McLaren before the first corner (their experience in the sodden Grand Prix races this year was paying off!). At the end of the first of the scheduled 50 laps the field was already well strung out, with Hulme 4 sec. clear of McLaren. Andretti had moved up from eighth to third, followed by Hall, Parsons and Revson. Rodriguez suffered early misfortune, dropping to last place and losing three laps when the rain drowned his ignition.
The highlights of the wet early laps were provided by a young Canadian newcomer, George Eaton, who was driving a Mk. 3 McLaren powered by a 5.3-litre Ford fitted with Gurney-Weslake heads, and by the experienced Mark Donohue. Eaton, who is only 22 and only in his first full year of Group 7 racing, surprised everyone by climbing from 14th to seventh on the first lap. Completely at ease in the miserable conditions and apparently unawed by the company he was keeping, he advanced another three places in four laps to a secure fourth place behind Andretti, McLaren and Hulme. Donohue provided some equally polished driving after spinning back to 18th place on the first lap when his throttle stuck. He regained 10th within three laps and was ninth the next time round. He took Bonnier on the seventh lap, splashed past Hall, Parsons and Revson by the 11th lap and then moved into fourth ahead of Eaton and 70 sec. behind Andretti on the 15th lap. Andretti, in turn, was only 2.9 sec. behind McLaren but Hulme had already opened up a 35-sec. lead.
By this point, one-third of the way into the race, the rain had stopped and the track was slowly drying. The dry-tyre gamblers such as Motschenbacher and Hayes began moving up from the back of the pack and Eaton found that his 5.3-litre engine was no match for the 7-litres powering Revson and Hall. At the halfway mark, with the track almost completely dry, Hulme led McLaren by 36 sec., with Andretti 9 sec. back in third place, being overhauled by Donohue at more than a second a lap. Revson was fifth and the only other driver on the same lap, followed by Hall, Eaton, Parsons, Bonnier, and then Canadians John Cordts and Ludwig Heimrath in Mk. 3 McLarens. Parsons’ engine expired on the 26th lap and when Bonnier’s engine went sour 10 laps later Motschenbacher and Hayes moved into the top 10 ahead of Cordes. In the process, Motschenbacher’s dry tyres enabled him to set the fastest lap of the race at 2 min. 16.0 sec., which was 1.1 sec. slower than Hulme’s lap record last year.
With only 14 laps remaining, the spotlight again switched to Donohue, whose McLaren-Chev. was now 26 sec. behind Andretti and gaining at 2 sec. a lap. By 40 laps the gap was down to 19 sec. and Donohue’s chances improved as the Ford in Andretti’s Lola rapidly lost oil pressure. The margin fell to 15 sec. on the 43rd lap, 9 on the 46th, 4 on the 48th, and then, on the 49th lap, Andretti’s engine scattered itself all over the track. One of the connecting rods sliced smack into the radiator of Donohue’s McLaren but Donohue survived the resulting hot bath for the final lap to take third place. Eaton, too, suffered misfortune after a fine drive, losing two places on the last two laps when his throttle pedal pivot bolt came adrift.
Even Denny Hulme was not without his share of drama. A suspected rocker arm failure struck three laps from the end and he began the last lap with the oil-pressure needle banging up against the zero mark. But he made it to the chequered flag first and for the third time in 12 months one of Bruce McLaren’s cars had registered a victory in its maiden race (the others being Hulme in the M6A at Road America last year and McLaren in the M7A at the Race of Champions in March). McLaren himself finished second, 34.9 sec. behind Hulme, and had the great satisfaction of seeing Donohue’s Chevrolet-powered M6A and Revson’s Ford powered M6B finish third and fourth. They were the only drivers to go the full 50 laps. Hall’s 2G Chaparral-Chev. was one lap down, followed two laps down by Motschenbacher’s M6B McLaren-Ford, Hayes’ McKee-Olds, Eaton’s Mk. 3 McLaren-Ford and Cordts’ Mk. 3 McLaren-Chev. Hulme and McLaren earned a total of £11,000, but the opposition appears to have grown much stronger since last year’s Can-Am. Until six laps from the end there were six drivers on the same lap and it will be interesting to see how they fare on a dry track.—D. G.