what a day check it out Please

[1979blkchevy]

Ok got up thismorning started up my truck and it made one hell of a grind/squeel sound then it stop let it warm up for a while no squeel or grinding sounds as it idles I get into the truck take off down the road and it did that squeeling sound/grinding sound again i stop the truck and got out popped the hood went to turn the truck off and the darn thing wouldnt shut off so i went out anyway to check under the hood and there was alittle steam coming from one of the valve covers so i got back in the truck and came back home and itmade that grinding sound all the way home about 4 blocks so i went to get some tools to unplug the battery when i came back the truck was already shut off!! Can annyone give me any ideas on what happen or what i should start replacing and ect thanks aot for everything