2006 Chevy Silverado Engine trouble but not sure what it is

I have a modified GM 350. It has an aftermarket race cam with the valve springs. It has forged pistons and rods. LS6 Stage 2 Heads. The engine is supercharged with 14lbs of boost. I've had the setup for over a year and it has worked perfectly until now. Last night as I floored it I heard a knock coming from the engine. At first I thought it was my supercharger but when I opened the hood the knock came from the engine (center of the engine but not sure). My first thought is something happened to one or more pistons. I called the place that worked on my engine before and they said they would need to look at it to really tell what happened. The guy told me it could also be one of the valve springs or rocker arms but he didnt think it could be the pistons being that their forged ( he didnt say it couldnt be either). The vehicle still runs but I turned it off to prevent further damage. What could be the issue in your personal experiences.

Oil level is good.