Yes, PLEASE save those! Please measure the diameter of the bores in an undistorted area as precisely as you can. And please measure the thickness of them at a edge (not in an area where they are embossed.) Let us know...
BTW, OP, have your heads checked for flatness.
Yes, could be either the bolts working looser or some detonation on regular fuel and/ot too much ignition timing.
Yes, I have seen head gaskets made like those.. and that was my 1st thought too. But these seems to have moved some as they don't look consistent hole to hole.
