This is one of the things that happens when an engine is run with low or no oil pressure. First thing I see when the head comes off is the No.1 piston laying to one side of the bore, with a much bigger than usual gap on the other side.
The piston skirts usually hold them a little straighter than this. That noise I was hearing was the pistons rattling around in the bores. Once I pulled the pistons, the cylinder walls look so bad it was a wonder this engine had enough compression to run.
I ran a bore gauge down each cylinder. The good news is the largest diameter is well within spec for a set of 40-over pistons. There are what appear to be some cracks. Hopefully those will turn out to be surface stuff that will hone out. Time to pull the crank and get started with a hone. This was starting to look like a cheap fix, but pistons for this engine are something like $150 EACH!