Grinding, " diesel " noise under valve covers

Crawled under it running. Caint really hear it down there.... I'm going crazy ( crazier). And here's the thing, I caint really remember it not doing it. But it all hinges on that damn dizzy with to much advance.my Bro said it didn't sound like that when we shoved it in this body. Said it sounds like to much timing. Cranked the timing down. The sounds still there. The mill don't have 3000 miles on it I'll bet.