Grinding, " diesel " noise under valve covers

What does it sound like when completely warmed up at operating temperature? Does the noise subside any?
Honestly, Rob, i haven't got her up to op temp, in a while! Did a shifter, front end, and then caught that **** dizzy issue. However, I was mapping timing the other day, with my gal reading tach, and operating throttle, for a bit. It Seemed to be quieting.. but I wasn't specifically looking for/ at that. And I didn't look at temp ga. But we mapped it, several times, up to, and over 3k