Symptom: Squealing sound from back of the motor when running at operating temps. When the engine speed rises a few hundred RPM's past idle, the noise gets louder but stops at higher rpm's.
We ran the engine with the trans off the car to rule out that.
Freshly built motor! When my buddy tried to take it back to the shop that built the bottom end for him, they were out of business. This is bad luck for him as the motor has less than 100 miles on it.
ANY SUGGESTIONS?
Main seal?
Main's or their bearings?

 

Could possibly be your pilot bearing. Next time you do a clutch put a new pilot bearing in. I wouldn't worry about it, it just gets annoying.

 

I've seen cam bearings and lifter wheels make noises like that. I put a cam in a dyno engine one day in 1995 when we were swapping like 3 cams a day and testing all of them for power. Forgot to lube it, it squealed and it never stopped making noise. Can't remember what I did to fix it. Anyway, I would do the lifters first, if that doesn't fix it pull the cam.

 

well, i took a look at the motor this afternoon. seems far fetched, but i saw that the motor did not have any pcv. he had put ported 241 heads on the car and recieved some valve covers that did not accept his factory 98 pcv hoses. there was no pcv relief on this motor what so ever! the fresh air hose from the TB to the valve cover was actually placed on the intake manifold from the valve cover. i put in on the TB, and took his oil fill cap off.
we started the motor and let it run for 15 min. long behold, the squeallin' was not present!
i can't believe the noise that the motor was making was preasure being built up!
a Metco valve cover breather is on order and should be here next day air. we are going to bolt the trans back up tomorrow and hit it hard on the road to see if this solved our issue.

 

good find