The belt and #2 misfire are separate issues, so I'd investigate them as such.

For the belt, have you relieved tension on the belt and spun the water pump by hand to see how it feels? While the belt is loosened, I'd probably spin each pulley by hand to see how they feel. Any chance you have a mechanic's stethoscope? Pretty easy to hear how quiet each pulley is that way and pinpoint the noise, but something is wearing on that belt. I'd also use it to listen for the ticking on the valve cover or head.

For number 2, maybe swap the coil/injector/plug/wire to a different cylinder to see if the problem follows those items?

I'm leary of lifters now with so many going bad on cammed cars in the past year or two, but most are the stock ones failing.

Since the #2 misfire is more serious, I'd pursue that one first before doing anything with the belt. No reason to run the engine more than needed listening for belt noise when more serious damage might be occurring otherwise.

 

Since the #2 misfire is more serious, I'd pursue that one first before doing anything with the belt.

I agree with this. I suspect the chirp was a lifter wheel sticking and scraping the cam lobe. If it has worn down enough there will be tick. I would pull the valve covers and check the preload. Look for a loose rocker.

 

I had identical issue, thought I had a belt chirp. Turned out to be a much more serious problem. Drain the oil into a clean pan and inspect for glitter. good idea to cut the oil filter open and inspect that as well. Remove the belts entirely and start the motor just long enough to see if chirp persists. #2 is right next to the tensioner and had me believing that was making the noise. Nope, is was the sound of a bad lifter destroying the cam. here is my experience with it:

https://www.ssforums.com/threads/chirp-not-from-belts.199440/?post_id=3675895#post-3675895

 

Agree 100 % I have seen a few LS engines with "Belt chirp" be Lifter failure in my years working on them,

 

Lifter. I’ve seen this several times - including my GXP under warranty.

 

Tensioner looks to be in a normal position. Check on the Harmonic Balancer to see if that may be causing belt issues.

 

Thanks to all for suggestions and troubleshooting.

Swapping coils and checking the plugs did not change anything, belts off sound is still there, sick to my stomach now. Contacted a local shop with SS/G8 experience as I'm well out of my end of the pool now. I'm a mess worry about this, what's the worst case scenario? cam, lifters, rods?, heads? Am I in this for another $10k? Ugh

 

You're looking at this all wrong. We're not talking worst-case scenario, we're talking best-case scenario. A nice 418 cubic inch forged long block with a beefy supercharger up top. Let's not talk about money though...
Seriously, you're likely looking at a full rebuild, or picking up a new long block. Once those metal shavings run through the engine, you've likely contaminated all bearings at a minimum. Usually the bearing material is softer than the crank and cam, so those will often be okay unless the lifter damaged the cam (likely). Disassemble, clean, new bearings/seals/oil pump, etc, reassemble. I'd get quotes and compare the cost to a new long block as the labor can add up quickly.

Edit: Looks like a new long block is running ~$8k, plus whatever labor. A used engine is always an option too.

 

I went through failed lifters on 2 different occasions. Had a shop repair it the first time. Came in at $4300 with OE replacement parts. The second time I fixed myself for about the same cost. Doing the labor myself afforded me higher end parts. this was at 61,000 miles. At that time the heads only needed the seats cleaned up and since they were disassembled I went back with new seals. I believe the cause on both occasions was oil starvation at high rpm, as well as spun lifters. In hindsight I should have went back with link bar lifters rather than 2110R drop ins. They were fine when checked recently while installing ported heads. And a high volume oil pump is mandatory.
I also learned the hard way that most solid pushrods come in at .010" under. So the best bet at getting them at the measured length is to order them from Manton. Short or limited travel lifters run much tighter clearances vs. the OE. Warning LS rebuilds are harmful to your pocketbook. And a high volume oil pump is mandatory.

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