Building on the success of the ‘Zerex Special’, Mclaren made a production run of Group 7 racecars known as the McLaren Mark 1 or M1A. After designing and racing the prototype, Elva was commissioned to a series of M1As which were raced by private teams.
The M1A used a spaceframe chassis with a tuned version of the aluminum Oldsmobile V8. Other details included Cooper wheels, uprights and steering arms, Girling disc brakes and a Hewland Gearbox.
Traco was responsible for engine development of the Oldsmobile V8. It was increased from 3.5 to 4.5 liters and when fitted with four Weber carburetors, produced 310 bhp.
The chassis was multi-tubular and square-tube spaceframe that was reinforced with sheet aluminum. The main chassis tubes also fed oil and water to the front-mounted radiators.
Bruce McLaren Motor Racing Ltd debuted their own M1 at the 4th Canadian Grand Prix at Mosport Park. It was fastest car on track that weekend, but suffered teething problems in the pitlane to finish 3rd overall.
After a returning to England, Frank Nichols of Elva Cars was commissioned to produce a run of replica cars known as the McLaren-Elva Mark 1 of which 24 were built. Meanwhile McLaren continued development of the car to produce the M1B.