How old are you??
From someone who worked summer jobs at the local Chevy "Conditioning Shop" for two summers, I can tell you that being 16-17 at the time, I was paid 6.00 to start (because the way I got the job was by my car being so clean), then got bumped the next summer to 6.50.
Are they asking to see your car first to "demonstrate the quality of your workmanship"??? If so, make sure you do a complete detail on it just before you go, it helps if you have a clean car yourself when it comes time to discuss pay/etc. - gives you a little leeway.
When you get to the dealership, make a point to stop outside the office of the guy you are going to talk to, and use a cali. duster and QD on your car before you go in. (if possible, adjust your tie in the fender)....
basically just brown-nose your way into higher pay, in any way possible. These chevy dealership guys like that.
Oh, and one more thing: GOOD LUCK!! :wavey