Help with noise

[1badc4]

I have made other post about my recent purchase of a 2001 Tahoe with supposedly spun bearing to drop my 5.3 with 183K out of my rusty Suburban in. the Tahoe motor doesn't really act like a spun bearing. great oil pressure and runs smooth, just has horrible knocking. tons of you tube videos of trucks with same issue. some cleaned with motor flush some had severely pitted lifter which also wiped the cam. I at the point do I just do swap or try to just fix this one? the noisy Tahoe engine has 158K miles on it. I first need to determine the problem with it. I have tries seafoam with no change, then I pulled valve covers and nothing is obvious there. next step pull the heads. does anyone have a good idea what the noise is. I am not familiar with the LS platform and find it remarkable that a pitted lifter can make so much noise. thanks for looking

 

[Kraig]

When you pulled the valve covers, what did you look for/see? Did you wiggle all the rocker arms to check for slip? Did you crank it over and watch all the rockers for motion? Run it with the covers off?

 

[Sasquatch]

Check your flexplate for cracks, I have only heard it a few times in person but that would would be my guess.

 

[Doubeleive]

my money is still on rod knock, go to a muffler shop and ask them if they can pinpoint the source those guys are pro's

 

[Big Mama]

At idle it sounds really fast to be a lifter. Does it get louder with more rpm? I noticed a dash light on when you got in what was it?