Need help with part numbers on cylinders.I bought these cylinders to do a 883-1200 conversion they are stock bore.The part number is a little hard to find solid info on #16871-99Y they came in a buell box with a buell label on it.They are stamped 1200 and HD on the cylinder.I have had one person tell me that they were part of the Screamin Eagle kit that included the heads and pistons,but he was not sure.If any one could tell me about them please let me know.Thanks in advance.