There is a noise when my car is in neutral (assume it is the throwout bearing) and goes away when the clutch is engaged. It comes back with acceleration. I've been told this is normal, but have had a previous Z-28 that did not do this. Any advice? If I leave it as is (and turn up the stereo to ignore it - ha ha) what problems can I anticipate, if any?

I also have some valves "rattling". Does this mean something is wrong, or does my car just need adjustments or a tune up?

 

Some rattle is normal, combination of the throw out and the antichatter springs on the disc. When it gets bad or worsens quickly you'll want to replace the clutch and the bearing.

Valve rattle is not normal, try to isolate the noise and find out what is causing it before something breaks.

 

had something simular once I think we replaced the pilot bearing......