Love to help but I'm not even sure what you are talking about. Are you talking about a cooling
manifold on your engine
, a tank switching manifold in your plumbing
, or something else? How about a picture, or at least a manufacturer and model number of what you currently have?
I'm suspecting you are talking about the plumbing
option. If you can't find a replacement you can always replace it with a few individual valves plumbed with T's. Lots of boats use that setup.