Used GM alternator pulley.  This is a factory pulley removed from various GM CS130 alternators.  This is a 6-rib serpentine pulley, fits the .67" alternator shafts and has a 2.2" OD at the grooves.  Proper spacing is required when changing pulleys.  Typically, installing a smaller diameter pulley will speed up charging and installing a larger diameter pulley will slow down charging.  Fits the following:

88-97 Camaro (V8 models)
88-97 Firebird/Trans Am (V8 models)

84-96 Corvette (V8 models EXCEPT ZR1)

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