LFP Alternator Pulley 2003-04 Mustang SVT CobraThe LFP Alternator Pulley is used with aftermarket Crank Pulley Kits to reduce alternator revolutions. As you increase the diameter of your Crank Pulley, your alternator pulley will have more revolutions. Over time, the increased revolutions may cause your alternator to over-spin. Prevent it before it starts by adding an oversized LFP Aluminum Alternator Pulley.Application Chart:2# Ring None4# Ring 3.20''6# Ring 3.50''8# Ring 3.70''Features: