WTF is this THING in our 340 ?!?!?!?

Well, here is a pix of the 'thing' and an unmolested Holley check valve. It looks like the same item; the one that got into the engine must have fractured when it was crushed and made it look like something else. Well, we do know that we indeed have a good tight quench gap!

Thanks to all for the consultation.... it sure solved the mystery.