Let me know what you think but a sound you hear in the video, thank you.

My buddy's chirp was from misalignment of the belt system, alternator etec.

After watching and listening to the vid it sounds like a kind of vacuum or exhaust manifold leak

Start by eliminating all the belt and tensioner possibilities people will suggest, but I think you have a bad valve lifter causing the chirping noise.

I second extrapilot. Take both belts off. If the sound persists, it's not any of the accessories. If it goes away, you've just narrowed it way down.

It does sound like a lifter roller, though I would expect to see elevated iron in your oil analysis from cam lobe erosion. How long has this noise been going on?

You can simply spray some water on the belt and if it stops chirping for a few seconds it's the belt system.

Subscribing for follow-up info. Good luck OP. Please report back with any findings.

My car had it for several years before I sold her - never had any issue - I pinned it down to the alternator (guestimate) but it never ended up failing me. Bottom line is that I would not worry about it IMHO.

a loose spark plug can cause this - as well as a bad belt tension adjuster.

Could be many items:

Belts (take them off one at a time and see if it disappears)

Harmonic balance (or belt) - Many vette enthusiasts swear by Gatorback belts

Pulleys / tensioners

Hope this helps

Worst case, it could be a lifter that has failed. Its happened to me. If it is, don't run the engine. While its running its grinding on the cam. Heads have to come off to replace

And the camshaft replaced even if it's slightly scored, at a minimum. Engine will have to be inspected for further damage if metal is found elsewhere, Good idea is to have the oil filter removed and cut open for inspection of the filtering pleats.

It's too difficult to tell what the sound is with headers. They make the valve train so much louder and really obscure the chirp.