Just wondering if it's possible to simply pull the head, take off the pan and pull the stock pistons (if the rings are damaged) and then simply replace them with othe stock pistons from a motor that is the same? What has to be done or is it even possible?

 

I would use new pistons and rings. And yes it is possible. Though if the rings are damaged the cylinder walls could be scored so you might want to get the block honed to clean it up.