What result are you looking to achieve? You don’t mention a running
or starting issues. Replacing just the rings in an attempt to push a
needle farther on a gauge can result in other unintended issued with
little rewarded in the end. As far as your knock I would suggest check
for any ware in the rods or wrist pin by watching the pistons after
removing the exhaust cover, thereby avoiding the possibility of a broken
head bolt.
Tubs
A "Boathouse Repair" is one thats done without having tools or the skills to do it properly.