The Chryslers (both 23 & 25) used rod length to adjust deck height vs. stroke, to use the same piston for different size engines.
This suggests that the longer strokes (230, 251, 265) can get 1/8" pop-up (or at least higher deck and tighter quench) by simply using the rod from the next shorter stroke (218, 237, 251 respectively).
Yes, it would require milling a dome relief in the head, and there may not be enough metal for safety. Alternatively, a small improvement by taking some off the dome itself. How to tell? Drill a hole in a junk chamber and see where you break through.
Anyone heard of this?
