The Canadian-American Challenge allowed unlimited engine size and unrestricted aerodynamics. By the end of its run in 1986 some cars claimed 1500 horsepower. Aerodynamic wings, ground effects, effective turbochargers and aerospace materials were developed and became fair game, but the cars were required to have two seats, enclosed wheels and basic safety equipment. Son Ted, Donnybrooke Motors general manager/mechanic, tended the company’s McLaren M1B No. 22 at Road America for its driver/owner.