The piston /bore are prolly worn, egg shaped and tapered.
And the crank shaft also needs turned undersize and a new undersize rod.
there are no "valve stem seals"
Quit agonizing about it and take it apart, and send it to the machine shop.
Or put in ear plugs and think pleasant thoughts till it puts a window in the block creating a boat anchor.
They will tell you what it needs then order the parts from the guy on ebay,
Bakt4kids, everything comes in a kit for around $160
Most everyone has good things to say about his parts.
Good luck!
