Grinding, " diesel " noise under valve covers

Come to think about it, the timing cover, and eccentric, were prolly robbed outta a 318 I had layin round. I do not remember buying one, but may rember cleaning one,, and changing the seal w/ a piece of maybe 2" sch 40? and Definitely do NOT recall buying a FP eccentric. But I may have. I don't usually use used wear parts. But I could have been " outta time and money" lol and actually, earlier, I found the sound loudest ( by ear) under carb, over the front top of ( not a valley pan like a big block) the bottom of the Holley Strip Dom.... I Pray that's it!