Sn 92 with upgraded impeller

Whats up fellas? Im new to the site now by a few days. But i have a question about my sn 92 on my 89 gt. Would it be possible to put a slightly different pulley on this to make more power or not? I believe it has the origanal pulley on it. alhough the impeller was upgraded a while back. Im just looking for a little more Hp. I ran a 13.2 with the stock motor, exhaust, Mickey T's street cheaters and the supercharger.
I would love to crack the 12's with the same basic setup. Any help would be much appreciated.

Measure your pulleys to be sure of the sizes. (Crank & Blower) I can probably get you another 25-30 hp, also what are you using for gasoline(State and City not listed) and for timing control.