On September 1–2, in conjunction with the Champ Car race in Assen, Netherlands, the Dutch Grand Prix will hold a special historic support race known as the Historic American Cup.
Organized by Tachyon Motorsport, the Historic American Cup will include American racing cars (GTs and Touring) built before 1966. Other American-powered GT and Touring cars (i.e., Bizzarinis, et al.) can petition the organizers for inclusion.
From more info, contact http://www.historicamericancup.com.
