I am totally vexed!!! Ever since I finished my 351 swap, I have had this belt squeal problem. I have new idler and tensioner pulleys, smog pump eliminator pulley, new water pump, new power steering pump and pulley, plus a new belt. When I start the engine, the belt screeches and the alternator doesn't show a charge. It'll read 10.2 volts. Now I can pull the alternator plug and the screech goes away. Or I can use my battery charger and while the engine is running, move the selector switch up two clicks from 2 amps/trickle charge to 40 amps and the belt screeching stops and the voltmeter will read 14.6 volts. I have replaced the alternator three times(new units, not reman) and this time I even tried replacing the voltage regulator to a soft start unit and still have the same belt screech problem.....I'm really lost at this point..please help!!!!