Proflow 80mm machined steel Ford replacement pulley is designed to mimic the original alternator pulley found on Ford Falcon GT models. These pulleys can be used in any application outside of restoration purposes to reduce alternator speed in high revving engines. It is a good universal mid range diameter pulley for a street driven high rpm engine. This is still considered larger for high RPM engines. (most std pullys are around 50mm). If you want to further protect you alternator from overrun , you may consider using our PFEP8868 which is bigger again. 

Example: if you are turning 7000rpm and have a 6 inch crank pulley with a 2 inch alternator pulley, your alternator is doing 21,000 rpm!