It all boils down to what you want to spend and what your goal is. Personally I would rebuild it all. If you are on a budget just Replace main crank seals, check for wear on piston walls. If it's within moderately lower than acceptable levels then Maybe throw some new rings in after you hone the walls...Better than nothing. If you go all the way and plan on doing it right then you should replace crankshaft bearings, polish crank or grind depending on wear, measure oil pump tolerance for wear. Going all the way may lead to having to boring the cylinder walls and replacing pistons, not always necessary but likely if the engine has never been rebuilt. Checking oil pump is important as you don't want that failing a month after you put it all back together. Machine surface of head and block to achieve true flat surface. If you machine surface consider a thicker head gasket as its a little more forgiving and hold up better over time. Oh...and change the pilot bearing in the crank. Just my two bits. Sent from my iPhone using Tapatalk