I am working on a 99 K2500 Suburban 4x4 with a 454 in it, the guy did a head job on it and dropped something inside the intake while putting it back together, the thing he dropped in went to the piston and once he got it together he started it up, he cut it off immediately and took it all apart to get it out, he scratched the piston quite a bit, but now when he got it back together it makes an annoying ticking sound at idle, even when it's warm, you can't hear the ticking when it's reved up to about 2000 RPM, I am curious as to what would cause this ticking, any help is appreciated, thank you, I will post a pic of the piston when I can

 

If he scratched the piston quite a bit, then he also scratched the cylinder wall quite a bit also. With out hearing it, it is difficult to tell. It might be a valve tick or the piston scratches.

 

This is what the top of the piston looks like

 

Here is a video also of the ticking

 

Did he check for a bent valve head? Also could be a broken piston ring.

 

As far as I am concerned I dont think he did