Pulleys depends on how your car is equipped . PS, A/C etc.
Pulleys have part numbers stamped in them. Must be matched set to work properly.
Non a/c cars usually have larger wp pulley and smaller crank pulley, a/c cars have larger crank pulley and smaller wp pulley.
GTO restoration guide and websites will have the information about pulley numbers.
[email protected]
Sent from my XT1650 using Tapatalk