Need more hp!!

I've been looking to get a little more hp out of my 4.8, but I don't want to take the forced induction road quite yet. I was lookin into a cam or maybe new heads or a port & polish. Only problem are the damn California emissions. The only cams I can find for a 2000 Silverado 4.8L are all not CA legal. Any help or other upgrade ideas would be appreciated.

I'm a bit confused??? When you say no forced air, I hope you're not refering to a cold air intake system. Doing that would make more sense than messing with the cam or heads. I'm in CA. I agree emissions can be a &!+(# here, but there are ways around it...dual exhaust, cold air intake and a good tune!! These can do a lot.

Forced induction aka supercharger. I've already got the basic mods (air intake, headers, exhaust, programmer, etc..its all down there in the sig)

STS turbo, nice and simple set up. Installs in less than 8 hrs. Get mpg and power out the Ass....