You can change your pulley size to a smaller unit if needed and that will increase your overall boost on the car
depending on the SC that you have. Some do have limits on the boost like your head gaskets do also.
That being said, you just cannot put a super small pulley without taking into consideration other things.
Do you know what the original pulley is on the SC now?
Is it a Maggie unit?
You will be pumping more air, so you will need more fuel to go with that air to get the right AFR.
Also you would most likely need a tweek to the tune of the car or you could go lean, which is not a good thing!
On my past blown cars I just swapped to a smaller pulley and had a re-tune which adjusted the timing and
the fuel to stop getting any KR (knock retard) by the PCM.
The KR on GM cars when it kicks in has a very slow recovery time which really kills off the timing and performance
unless the tuner adjusts the recovery time to a smaller cycle.