When accelerating there is a screeching noise?

Hello, the first thing that comes to mind is the serpentine belt. It's hard to say for sure without actually hearing it. Would it be possible for you to upload a recording of the noise?

Okay, thanks for the update. With the belt off, that eliminates any belt driven accessories. Do you hear any chirping type of noise at idle? I ask because the cam synchronizers have been known to make noise at higher mileage. But, even if there is no noise at idle, this could still be an issue.

Yes, but I would go ahead and replace the synchronizer assembly sooner rather than later. It's possible for it to seize up, although I have only seen that happen a couple of times. Now, there is a special tool that is used to time the synchronizer, but if you are very careful and mark the old and new parts with a paint pen you can do the job without the tool. It must be installed exactly as the old one. Just don't turn the engine with the synchro removed.
Mark the rotor to housing position and mark the housing to cover position. I wish I had a better picture, but I hope this helps.