Hi Jdol
I hope you have had some success with your hunt for a new exhaust manifold.
I would like to point out that the rust/corrosion/deterioration of you manifold is abnormal.
This would indicate a consistent cooling water leak onto the manifold.
You want to ensure that your new unit is leak free and hopefully the corrosion has not affected the head.
Here is a photo of my spare manifold and water injection elbow.
This unit is at least 30 years old and shows how a dry unit should look.
Will add a photo of my fitted unit when I get down to the boat.
gary