It's an ex imca 602 crate engine
Finished its last race in the top 5 even with that hole in the valve. I'm guessing something from the carburetor came loose and went through the engine.
I'm installing a 480 lift cam that was suggested by a few different Vortec guys and will be keeping the compression as close to 9.5-10 :1 as possible even if I replace the pistons. It's going to go into my 79 Z28. Just a nice little hot 350.
Looks like whatever went into the cylinder went right out the exhaust along with that piece of valve. The piston and cylinder wall look good from what I can see in the pic. I would fix the head/valve and run it.