Really? This is like the third or fourth "how small a pulley can i run" thread in the last week. It must be a rash or something going around.

But alas, to answer, what year? L67 or L32? How is your car running now? Everything up to date maintenance wise?
Hypothetically, with a full exhaust (including headers and hi flow cat) on a gev v maybe a 3.2. No headers 3.5. Gen III 3.1 maybe lower?
Hard to say and these threads suck btw. SCAN THAT MOTHERF***** AND FIND OUT.