Development Blog, Grand Prix 1973 Grand Prix BT42 Development: Day 5: Wheels and Exterior details Posted on April 5, 2021April 14, 2021 by admin 05 Apr Day 5: Today we’ve finished the wheels and added more exterior details. Next stop: The interior. Grand Prix BT42 Development: Day 4: Rear Suspension and Wing Grand Prix BT42 Development: Day 6: The Cockpit