Sorry to hear that.
Failed piston rings are not very common on this design from what I have seen over the years. Hopefully the cylinders are not scored badly.
i know have 2 mowers with this engine one is over 10 years old
There is a chance the heads have warped in the pushrod area near the cylinders. That was an issue on some due to repeated overheating
As this engine been run in dusty with the air cleaner off for any length of time?
not sure but there was a build up of dirt in carb intake
EDIT: Don't overlook the breather valve located under a cover on top of the engine block. These have been known to fail the flutter valve and the gasket before.
there is a lot of dust/dirt build up on the cover of the breather valve
Having 130 PSI compression just does not sound like failed rings. Scoring of the cylinder is still a possibility.
