It's evap, not eval. It's part of the evaporative emissions control system, which captures fuel vapors from the tank and fuel delivery system and feeds them back into your engine to be burned as fuel instead of letting them escape and go unused/pollute.
It was easy to replace on my 2002 GMC Sierra and shouldn't be too hard on the Camaro either. It's not something deep inside the engine where you have to take everything apart to reach it. It's a fist-sized gizmo bolted to the underside (probably, or possibly under the hood) with a few hoses and wires going to it. I imagine on the Camaro it's in a tight spot with not a lot of room to work, but probably no need to take stuff apart to reach it.
Here's what it might look like:
Threaded Mode