Larry Jaques wrote:

Don't go by the piston, go by the bore. It sounds like your engine is
in fairly good shape, but check for elongation perpendicular to the
crankshaft. Bores become oval from wear, where the connecting rod
pushes 'em up and drags 'em down the opposite sides. If you bore it
out, you'll need all new pistons by default.

The piston is wobblier perpendicular to the crankshaft that it is in the
parallel direction, which suggests to me that there's some significant
wear. Also, the compression isn't great. But the bore itself looks fine,
hence the bore gauge purchase.

Chris