You probably know what i'm already thinking, i know, i always bring up the ls1. but...

If you go with a mild cam, you're probably going to have to install retainers, springs and maybe harder pushrods. That's about 700$ from ls1motorsports.
Your headers are say 600-700$ right?
That's already $1400 bucks. That's if you install it.

How much HP did you find out that will give you? I'm guessing 25-35 from the cam, and 15 from the headers. Have you thought about buying an ls1 longblock for less than $1500 easy?

Just trying to explore all the possiblities. You'll start off with more HP and have a better baseline for modding that badboy.

If you want to wake that 4.8 up a little bit, get the roller rockers, and some 4.10 gears, they are fun and awesome for light to light, and they still give you low rpms on the highway.

I'm not trying to bust any bubbles, just trying to help, those 4.8 and 5.3's are badass too, all the gen III engines are badass.

let us know what you decide,
btw, you know i'm an ls1 whore, so don't be offended, hahahaha, i always respond with that answer,

have fun,

allen