12-050-01 may be a better number to search oil filter suppliers for a substitute. The Kohler oil filter 12-050-01 was superceeded to 12 050 01-S1. Fram still has the old number and it crosses to Fram filter PH8172
Cross reference to what other filter? As you do not list this information, go to the store that sells the brand filter you want to use. They can tell you the correct filter that cross references with the Fram filter.