That's my truck, it's an LT1, not an LS1. That's the factory LT1 waterpump, it's gear driven from behind, not pulley driven like the old small blocks so it kind of looks like an electric pump.
the LS1 is going to fit differently because it's a whole new engine, redesigned from the ground up. Pretty much everything is different, but physically they're similar in size. I'm pretty sure the mounts are different so 350 mounts wouldn't work.
This is an LS motor.