The Castrol Grand Prix, the ninth round of this year's Can-Am series was run at the challenging Laguna Seca circuit in Monterey, California, and marked the first time this season that all the main contenders appeared at the same time. In addition to Denis Hulme and Peter Gethin in the works McLaren M8Ds, Chris Amon was making his second appearance in the works STP March 707, BRM had two cars for George Eaton and Pedro Rodriguez, Eric Broadley was present to help Peter Revson with the sorting of the long-wheelbase Lola T220, Vic Elford reappeared in Jim Hall's "vacuum cleaner" Chaparral 2J for the first time since Atlanta, and Jackie Oliver reappeared for the first time since the second race at St. Jovite in a new version of Peter Bryant's Ti-22 titanium car. The first seven cars were little changed since the eighth race at Donnybrooke but the Ti-22 was an entirely new car, not just a modified version of the one in which Oliver chased Gurney to the flag in the first race at Mosport and then crashed on the first lap at St. Jovite. Reading like an advertisement for one of the Big Three's new models, the new Ti-22 is longer (by 2 in.), wider (by 4 in.) and lower (by 1 in.) than the original car. The mid-section of the chassis has been strengthened by titanium sheet stiffeners in the pannier fuel tanks; the 8-litre Chevrolet engine now acts as a stressed member (with the assistance of diagonal braces); and the front suspension has been changed to leading rather than trailing lower radius arms to provide greater strength under braking (one of the few weak points in the original car).
Although Laguna Seca is very short (only 1.9 miles), Jim Hall, Stirling Moss and Bruce McLaren always considered it one of their favourite circuits because unlike most artificial American road courses which tend to be a series of straights connected by corners that are frequently too sharp–Laguna is curving almost continuously as it skirts a former dry lake, climbs the side of a hill, rides along the crest, and then plunges back down to the lake bed. These almost continuous curves do tend to make passing difficult but, combined with the changes in elevation (250 feet difference between the highest and lowest points.), they also make the circuit ideal for Hall's Chaparral because the car's ground effects system is in almost continuous use. Elford lost little time proving this point and, despite the fact that he had never driven the circuit before, he ended the first day of qualifying as the only driver under one minute and the possessor of a new qualifying record of 59.4 see. (The old records were 59.53.sec. or 114.898 m.p.h. by Bruce McLaren in qualifying and 1 min 02.19 sec. or 109.98 m.p.h. by Hulme in the race, both set last year in McLaren M8Bs.) Hulme got down to 1 min. 00.6 sec. before encountering suspension trouble and Revson showed his Lola wasn't far off the mark with 1 min. 01.2 sec.
On the second day of qualifying Elford completed the demoralisation process by lowering his time another 6/10ths of a second to 58.8–three-quarters of a second under McLaren's 1969 record and 1.8 sec. under the best Hulme had been able to achieve (and considering the shortness of circui., the Chaparral's superiority is even more evident). Hulme did not improve on his time partly because he was busy running in another of the "special" engines referred to briefly in the Donnybrooke report. What made the engine special is the fact that the block is cast in a new, high-silicon aluminium alloy that is hard enough for the pistons to run directly in the bores without the use of cast-iron liners. The major advantages are a decrease in weight and much better heat dissipation. This special 390 alloy was developed by one of the McLaren team's sponsors, the Reynolds Metals Co., and is the same as that used for the engine in Chevrolet's new Vega. The McLaren/ Reynolds blocks are based on the regular Chevrolet design and the engines are built up to a 7.6-litre capacity. Gethin, meanwhile, had equalled Hulme's time of 1 min. 00.6 sec., Oliver had shown the soundness of Bryant's new design by equalling Revson's time of 1 min. 01.2 sec. and Amon had become sixth fastest with 1 min. 01.8 sec.
By this time, McLaren team manager Teddy Mayer and several others were muttering loudly about the Chaparral and openly considering a protest on the ground that its vacuum fans constituted movable aerodynamic devices and as such are banned under Appendix J. On Sunday morning, however, this controversy was postponed to another day when, during a warm-up session, a connecting rod punched a hole through the side of the Chaparral's main engine and the car had to be withdrawn because the four-to-six-hour change could not be completed in time. The Chaparral's withdrawal took most of the sting out of the competition and it was again the Gulf orange McLarens of Hulme and Gethin that charged in front, closely pursued by Revson and Oliver.
Amon quickly lost touch with the leaders when his brakes began to disappear on the fourth lap (a repeat of his Donnybrooke problem); the veteran Chuck Parsons held down sixth in his Lola T160/163; and Rodriguez's BRM took over seventh after Eaton suffered suspension failure. There was no change among the first seven cars for almost half the 80-lap, 152-mile race but on lap 35 Oliver squeezed around Revson and three laps later everyone advanced one position when Gethin spun off and could not restart. Oliver spent the second half of the race relentlessly harrying Hulme and although he closed the gap to as little as two car lengths at one point and set the fastest lap of the race at I min. 02.4 sec. (not a record), Hulme was in full command of the situation all the way and took the chequered flag 1.2 sec. in front to win his second Can-Am championship in three years. Oliver's Ti-22 was the only other car on the same lap for a very creditable second place in its first outing. Revson was third, one lap down, Amon fourth, two laps down, and Parsons, whose ignition became erratic during the final quarter, lost fifth place to Rodriguez on the final lap by 1.2 sec.-D. G.
Can-Am – Round 9 – Laguna Seca
1st:D. Hulme (7.6 McLaren M8D) .................... 1 hr. 25 min. 58.8 sec. – 106.07 m.p.h.
2nd:J. Oliver (8.0 Norris Ti-22) ........................ 1 hr. 26 min. 00.0 sec.
3rd:P. Revson (8.0 Lola T220) ......................... 79 laps
4th:C. Amon (8.0 March 707) .......................... 78 laps
5th:P. Rodriguez (7.6 BRM P154) .................... 78 laps
6th:C. Parsons (7.6 Lola T163) ........................ 78 laps
7th:T. Adamowicz (7.6 McLaren M12) .............. 77 laps
8th:G. Wilson (7.6 Lola T163) .......................... 77 laps
9th:D. Causey (7.0 Lola T163) ......................... 76 laps
10th:G. Lawrence (7.0 McLaren M12) .............. 76 laps
Fastest lap:J. Oliver (8.0 Norris Ti-22), 1 min. 02.4 sec. – 109.62 m.p.h.