I’m going to disagree that those marks are piston locator marks. I blew up the first picture and you can clearly see fresh shinny metal on the piston and displaced metal on the block.

I would pull the head to see what is really going on. It only the cost of a few gaskets and few hours of time.
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Damaged piston

Phil
Moderator, The Engine Shop, Interiors and Project Journals

1952 Chevrolet 3100, Three on the Tree, 4:11 torque tube
Updated to: ‘59 235 w/hydraulic lifters, 12v w/alternator, HEI, PCV and Power front Disc Brakes
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