You could try Regel Corporation. It has been some time since I ordered anything from them. ( I got tired and don't run much, so don't break anything 😉) I was told the manifold on my one 9u was from them when I bought 15 years ago. They are on the parts suppliers list on this site. Which I can never remember how to get since the new software here.
This may work yet 800 824 2164.