As often happens in the Can-Am series, the entry and the interest begin to perk up as the series heads towards the final races on the West Coast. This year was no exception and a number of new or improved cars made their first appearance at the eighth round of the 10-race series. The race was held at Donnybrooke International Speedway, a circuit new to the Can-Am series (though it has been used before for TransAm and Continental events) which is set amid a pine-clad resort area in Minnesota. It is a wide, completely flat circuit, three miles in length, with a 4,000 ft. pit straight (which doubles as a drag strip) and an interesting variety of 10 turns that includes two long sweepers taken flat-out in the Can-Am cars (185 m.p.h.).
Both Denny Hulme and Peter Revson needed new cars following their crashes at Road Atlanta. Hulme’s was another M8D, built up by taking the chassis tub from the new (and as yet unraced) M8E and adding the 4 in. wider M8D suspension. Revson’s new Lola, although still known as a T220, was actually 10 in. longer in the wheelbase (following a modification Frank Gardner found worked so well in his Formula 5000 Lola). The chassis tub is unchanged, the extra length all being added forward of the front bulkhead, but Revson said the new car was much more stable. The old car’s pitching tendencies had gone, the understeer was down considerably (though still a bit too much) and the braking much improved. Another new car was a second works BRM Type 154, driven by Pedro Rodriguez, which incorporates all the modifications made to George Eaton’s car in the first seven races. Not new, but making its first appearance this year, was the Ferrari 612 campaigned last year by Chris Amon. Driven this year by American Jim Adams, it should no longer be known as a 612 since it is fitted with a 5-litre V12 as used in 512S.
The newest of the new cars, however, was the works, STP-sponsored March 707 for Chris Amon. The car differs from the first one built in having more vertical front coil spring/damper units to reduce excessive suspension movement. The car is low but both longer in the wheelbase and wider in track than most others, with adjustable dive-planes on the front body section and a car-wide wing mounted on small fins atop the rear body section. The chassis is 20-gauge aluminium riveted to magnesium bulkheads front and rear, and designer Robin Herd has followed current practice by using the 7.6-litre Chaparral Chevrolet engine as a stressed member. Two diagonal braces on each side assist the engine in this function and the rear suspension is attached to subframes over and under the Hewland transmission.
The weather was wet, cold and miserable on the first day of practice and this, combined with a rash of mechanical failures on the second day, diluted the usual qualifying battles. The qualifying record was I min. 32.5 sec. (116.757 m.p.h.) set by Al Unser in a USAC race last year. Hulme and Peter Gethin in the works McLarens had hardly got into their stride with laps of t min. 30.9 sec. and I min. 31.7 sec. respectively, when both were sidelined with mechanical trouble. Hulme’s engine, a rather special lightweight one, began to digest its innards when a rocker arm broke, while Gethin’s transmission was bent on self-destruction. Amon’s March, meanwhile, had been wheeled away for hasty repairs when the left lower front wishbone pulled away from its mounting point before Amon could record any times at all. Revson was the only contender with few apparent troubles (both BRMs suffering from rocker arm and/or tappet failure similar to Hulme’s), and the American proceeded to put the Lola on the pole with a lap of 1 min. 30.8 sec. (118.943 m.p.h.). The March then reappeared and after four slow laps to check out the front suspension repair, Amon put his foot on it. On his fifth lap the 707 turned 1 min. 30.9 sec., equalling Hulme’s time, but just as the lap ended the right rear suspension upright cracked. It turned out to be a faulty casting rather than design failure and the March was on the grid the next morning.
Although Hulme’s car had been fitted with a smaller 7-litre engine, the McLaren team leader was anxious to make up for his “d.n.f.” at Atlanta and penalised finish at Road America, and when Revson fluffed a shift on the rolling start Hulme immediately shot to the front and left Revson, Gethin and Amon to dispute second place. Indeed, the entire race was a battle for second place as Hulme, lapping consistently under his qualifying time, led every lap, set a new lap record of 1 min. 29.5 sec. (120.670 m.p.h.) and a new race record of 117.570 m.p.h. Revson held second for nine laps until a broken throttle spring sent him to the pits and down to 17th place. Amon then harried Gethin for half the 70-lap, 210-mile race and shortly after the halfway mark actually put the March in second place for a dozen laps until his brakes began to fail. Gethin, nursing a doubtful engine, then recovered second place and held it to finish 59.4 sec. behind his team leader. The March’s very encouraging performance in its first race was marred slightly when a split fuel line brought it to a halt with only three laps to go, allowing Revson, who made a tremendous comeback, and Adams, who drove the 5-litre Ferrari with considerable verve, to claim third and fourth places. Amon finished fifth (Can-Am finishes are based on distance completed, whether running or not) and the only contenders not living up to expectations were the BRMs. Eaton retired after only two laps with broken rocker arms and Rodriguez, plagued by the same trouble, fell steadily from fifth at the start to ninth at the finish.—D. G.
Can-Am – Round 8 – Donnybrooke, Minnesota
1st:D. Hulme (7.6 McLaren M8D) …………….. 1 hr. 46 min. 10.2 sec. – 117.570 m.p.h.
2nd:P. Gethin (7.6 McLaren M8D) ……………. 1 hr. 47 min. 10.2 sec.
3rd:P. Revson (8.2 Lola T220) …………………. 69 laps
4th:J. Adams (5.0 Ferrari 512P) ……………….. 68 laps
5th:C. Amon (7.6 March 707) …………………… 67 laps
6th:L. Motschenbacher (7.6 McLaren M12) …. 66 laps
7th:A. Dean (3.0 Porsche 908) …………………. 66 laps
8th:D. Causey (7.0 Lola T163) …………………. 66 laps
9th:P. Rodriguez (7.6 BRM 154) ………………. 66 laps
10th:P. Gregg (7.0 Lola T165) ………………….. 66 laps
Fastest lap:D. Hulme (7.6 McLaren M8D, 1 min. 29.5 sec. – 120.670 m.p.h. (new record).