Located at the front of the bonnet (hood) aperture. Early cars had 2x, later cars had 4x per car.
 
Part Name: Spider & Spider Veloce Bonnet (Hood) Conical Seating Rubber Buffer (Bump Stop)
AlfaStop Product Code: 1RU114
Original Alfa Romeo Part No: 1488.90.017
Model: Guilia 101 Series, Giulietta 750 & 101
Quantity Per Car: 2 or 4