Billet Aluminum V-belt Alternator Pulley and Cap Ford Big Block Engines with Alternator Only This is a 1 groove, V-Belt alternator pulley for Big Block Ford alternator. Use when running alternator only. If you are running power steering, you should use part number BBF1ALT. Note: This pulley does not have an alternator cap. Grooves: 1 Pulley Diameter: 2.7" Alternator Shaft Diameter: 11/16"