The OP needs to read this series to get an idea of what HP a lot of work will net from a 3.8L:
- Tom Henry RS V6 Camaro Project

The OP did not mention if they're running a high-flow cat like Magnaflow's, that could add a little too if you're not already.

 

Just a note dont let HP numbers deter you from working on your car. Numbers dont mean anything except letting you know how much of an increase you get for your $$. Dont ever use them to compare vehicle to vehicle unless the numbers were taken on the same dyno, the same day, under the same conditions.

HP numbers are just something to impress the ladies and make you feel good. All dynos are set up differently and therefor give you different numbers.