Depending on the pin height in those pistons, you MIGHT be able to just go back to a standard crank and rods, without reboring the block and changing the existing pistons, leaving the heads alone.
You need to consider that even just honing the bores might make the bores .002 or .003 too big, then you are back into custom pistons and rings.
From the era, most shops rebored right to .030 over, because those simply were off the shelf pistons. You don't want to go over that with a stock block.
Just a thought.
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