Pull it apart. Is the chain real sloppy, bearings worn, ridge in the bore? Then determine its intended use. Everyday driver? performance? Light usage? If the walls and crank aren’t junk just fix the heads (or find a used pair), ball hone and through it back together. Many times a lot of dollars are spent to get it perfect. When in actual use you would be surprised what will work pretty well. Remember we are talking a 318 here.
Doug