Something to check is the length of your clutch cover bolts. Sometimes if you have some with just a little too much length, they will protrude through the flywheel and scrap on the oil pump cover. Way too long and they can even stop the engine from starting. Guess how I know? When the flywheel is pushed forward with the clutch release bearing engagement, assuming a few thousandths thrust clearance, the tips of the bolt just scrap the cover. A good scraping is quite a squealing sound.
HTH,
Mike Miller