It's heads for LT1. Label on the penny size discs attached to heads. No other visible labels. Spark plugs seems to be on slightly different angles, then stock (relative to header primaries). What heads these can be??? I'll try to make some pics.

 

Sounds like a heat tab. They are used by junk yards, engine shops and reman companys for the warrenty. If the heat tab is gone or melted they know that you overheated the motor and voided the warrenty.

 

Thanks! That's interesting, never thought about it, It's really make sense.