Did you find the missing stud? Is the piston cracked at all? I'd clean it off real good and see. If not then I'd put it back together. How's the valves look for that cylinder?
You got lucky. When I "lost" a bolt during a LIM job it shattered my piston on #1 to the point where all that was left was the rod and wrist pin beating the cylinder wall up. Yea, stupid I know but sh*t happens.
In my defense I thought I'd seen the bolt jammed down low and didn't think it made it where it did. Had I known I would have pulled my head before starting it at all. The 1K+ rpms it turns on startup is enough to destroy a piston in .000000002 seconds
