There's nothing stock about that engine transmission and/or rear end. Everything was pulled out that was stock and everything bought brand new because he blew up the motor. The stock one.
This is most likely the L99 that came in the car, which is the LS3 with DoD/AFM, all that crap removed, bigger cam, bored and stroked out to 427(or actually 426.xx) 4.125’ bore, 4.0’ stroke essentially making it a LS7, with a cam and probably other goodies like head work, intake and headers/exhaust. Really nice 5th Gen, I don’t even care if it is a 6L80. I should clarify that manual 5th Gen Camaro SS’s came with the LS3, automatics came with L99.
My truck has a built 80e and shifts faster than any dct or faster than anyone can shift manually. But I also have 3 cars with manuals. But I wouldn’t want a manual Camaro of that gen anyways. Just doesn’t feel like a car that would need one or drive good with one.
Camaros are cars meant for the drag strip, I don’t know if you have ever been too a drag strip but there’s a mighty fine reason everyone runs 3 speed autos…