Grinding, " diesel " noise under valve covers

The noise isn't valve train related.
Ok Rob. I'm Sorry, I'm chasing ghosts... So, at this point, I'm gonna break it down..i borrowed a mechanic stethoscope, and an endoscopic tool. My buddy ain't even used it yet. And he wants me to " cushion it " w / electrical tape, but said Don't block the side camera.
1) haven't warmed up to Op Temp, to " listen " for piston slap. Is there any specific area to listen to
2) I ain't cut the oil filter
3 )MOPAROFFICIAL said to listen to the bottom. Of head, next to spark ug, Scuffed Piston
4) I have no idea if it's a cam bearing issue or not. I hear it on both banks, but loud over cam chest in front of carb. All tests have been with Human ear, only mine..I Tried the 3/8 extension, nothing. Havent tried the stethoscope yet... ol Lady's sister got diagnosed w/ colon cancer/ lung cancer. Surgery tomorrow, but they said " they dunno what the outcome " will be. So I don't have help from my GF.
My Friend Doug,.a Ford Guy, one of best friends, has helped me spin Many a Wrench. And I've helped him too. With our job, and rain Thursday, looks like Friday will be the day we attack this.... Any Input on proceeding from here?
As Always, Thanks!