This is the son! Looking back, I found that my dad never replied! Sorry, he's super busy! Thank you all for your help! geezer101 was spot on! It came off a jet valve that - near as we could tell - melted in the jet valve guide, (it looked burnt pretty good, was missing the whole valve head and bottom part of stem, and had metal that had flowed into the intake holes in the guide assembly) and broke the jet valve "ear" of the rocker arm off. I bought and installed the eliminator kit!

Sorry if I used a bunch of terminology wrong, I couldn't find much on "jet valve terminology"!