Hmm.. It's a lame debate ..but ok..so without having the heads physically in front of me to see.. but let's think about this for a second ..this is an aftermarket head ind hard seat with hot rod mileage ..'low'... sinking that much? Not typical.
The j head is definitely sunk, has the classic double ledge where the valve od diameter starts wearing into the top cut leaving half of it behind. The old thing to do was to drop a 90 to put a cup around the exhaust so nothing came back in ...and that's what is there...indy cyl has been around for what 50 yrs or more. That's my opinion.