If you're running a Revo or Slayer the spring mounted header (part#5340X) is a great upgrade over the stock screw mounted one. I haven't broken a header since.
What are you using it in? Each pipe combination will have a different location for the outlet, pressure nipple, mounting location.
FWIW: The OS 11K carb has the ball end on the throttle slide lever. The OS11KR has a smooth throttle lever which is meant for the Revo