Even though we’re essentially certain the heads are fine, we still had one head with known damage from the nut going through the engine. It just turned out not to be on the side where he was adjusting the lifter. Since we had already ordered a replacement head, I could either return that or replace the damaged head. I decided to replace it.
I spent a couple of hours tearing down the right side of the motor tonight until it was at the same place as the left side.
I cleaned and masked the new head, then sprayed several coats of Eastwood’s high-temperature ceramic engine paint in gloss black.