Are the existing ones damaged? What's the need for replacement?
There were headers for older monsters. But many times they were part of a full system. I've seen some on ebay for 900s. But they are rare and usually very expensive.
If they are not damaged - just looking shitty you can get them looking a lot nicer. There's threads on cleaning them up, ceramic coats etc etc.
no not damaged, just look shitty and I rather benefit from a full system vs. slip ons.