Chasing a squeal, need opinions.

[x33rs]

Ugh...

I hate to say it but might want to pull the intake and have a peek at the cam lobes.

If a wheel has locked up it'll score the lobe pretty quickly and you'll be able to see which one is the culprit, eventually eating it down until the arms of the lifter that holds the wheel pin contacts the outer edges of the cam lobe. Makes a squeak or squeal sound that is hard to locate. Even had one where the engine was still running fine (hydraulic roller), but was making the noise. Had a locked up roller lifter and was eating into the lobe. I can only assume it was still running fine because the hydraulic lifter was still taking up the extra lash it was creating for itself. It only ran for a few minutes after the squeal started.

I really hope that's not the issue but I've seen this more than once.