i just got a 99 sportster xl 883 c and the guy said it was a 1200. i checked the casting number on the heads and one head says 1200 (closer to the rear) and the other says 883 (towards front tire). i understand it could be bored to the 1200 but is this common? maybe one head was bad? any suggestions or help? id like to get this bike moving a lil faster, my friend has the night rod and id like to keep up.