The Exhaust manifold bracket has rusted out at the manifold.

What is the fix for this? There is basically nothing on the manifolds to reattach it.

 

That brace attaches the transmission to the catalytic converters, not the exhaust manifolds. It's tough to tell from your image but it appears to have remnants of the cat mounts still attached. They may have just broken off at the cats.

As for a fix... Weld them back to the cats. You could also buy new cats, but then you would need to be able to get the remnants off the brace or just buy another brace.

Edit: It just occurred to me that you could be running test pipes. I have no idea if those come with tabs/mounts for that brace. I know the aftermarket cats that I've looked at do come with them.

 

They completely rusted off the Cats...just a nub left
Can a new mount be welded onto the CAT? I thought it looked like cast iron...

 

They look like steel to me but I could be mistaken.

 

Just have a muffler shop weld new tabs onto the catalytic converter, then drill a hole through the tab where it lines up with that bracket. Then you can just run a bolt and nut through the two to bolt them together on each side. Super easy fix.

Spray it down with cold galvanizing spray to keep it from rusting.