Depending on what year, engine and transmission there are allot of details you would not find on a reproduction. Even the rebuilt or others you will find have often been rebuilt using parts from different applications making them not correct. So finding a good core can be a bit of a challenge at times or you just get lucky. No easy button to push and simply order a nice correct one for your application in all cases. Some (depending on year and type) will have the main body stamped with the engineering number as well as the date so the reproductions will not.
