If anyone has read the HRM "Speed Demon" article, the piston shown is a bit of a puzzle (and the auto shop quality of the author leaves much to be desired).
The LS is, obviously a quench chamber with tilted valves, and a chamber shape & volume designed to keep the CR in line with high boost.
However: the dome is a bowl with a round island centered in it. In a valve face this is what DV called "penny on a stick". I think the island is not a compression bump that doesn't interfere with overlap flow, but something else. It may be relevant to Trick Flow etc. heads.

Picture here: https://hotrodenginetech.com/speed-demons-ablown-fuel-streamliner-motor

Before I make a guess, any ideas?