How Much Power Gain??

Im thinking about Porting and Polishing my Intake and Heads. Any idea how much power I'd get out of doing this? For my 5.7 TPI

All depends on how the job is done, do it wrong and you lose power.

Lets say it's done professionally and top notch. Any general idea? I'm still not sure if this is what I'll do. I might be getting new heads completely for more power. I just need more power out of the motor