Mark the LS engines don't use a vacuum referenced fuel regulator so the vacuum port should be left open (I noticed you had it plugged). It also states that fact in the aeromotive literature.
Good Eye, Ken -- yes I left it plugged for now since I've been doing a lot of cutting metal and fiberglass on and near the car.
Can you tell me what vehicle the emissions charcoal canister was sourced from? If it's a sealed canister then you are creating a vacuum in your tank with the way you have it hooked up to the air intake. The charcoal gets saturated with fuel and needs to be purged occasionally but I think having it draw air constantly might be problematic as your fuel tank empties.
It's this one: https://www.amazon.com/gp/product/B000C9I9GQ/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
It's a 3-line canister (tank, open air vent, purge). I have the purge line going to the intake pipe, but since it's before the throttlebody, the vacuum is pretty light so while it won't purge the can as well, it also won't be under intake manifold vacuum. If anyone has better setups for this I'm all ears -- this was the best my research could find to have at least something without going to a full setup with a purge solenoid.
Thanks!