Does anyone have any suggestions on how I can stop a loud screeching that happens after starting my 1978 Type LT, the car is extremely loud even though it recently had a brand new muffler attached, and the ground cable is getting extremely hot. This car has been parked for roughly ten years and I've installed a new starter and a variety of new gaskets, The vehicle starts however after a few minutes a loud screeching sound starts, sometimes the car will turn off and just continuously crank after the sound starts. Any help would be greatly appreciated thanks in advance!

 

Replace alternator/water pump belt and adjust tension on longest side of belt for about 3/8 inch deflection.
WD-40 works well also. You also might temporarily place a 50-0-50 ammeter on alt red wire to see how much alt is producing.
Could have an extreme electrical load on alt. I'm sure you've externally charged battery overnight.