292 Stock Exhaust Manifold

[Crazy Rusty]

I'd like to restore my original exhaust manifold to its previous glory but can't seem to find any information on it. I believe I understand how the flapper works though I haven't ordered a new spring for it yet (figure I'll test it with a heat gun) but I'd like to be able to take that all apart and clean it which doesn't seem possible. In the two pictures I circled bolts that were in there (one came out, one broke off) and was wondering if anyone knew what was supposed to be in there.

If anyone has any information or better yet, any high res pictures of this header (as there appears to be several versions around) it would be highly appreciated!

Thanks