Thanks for the pics. The rh manifold that you have there appears to have a crack in the middle. The rh manifold that I have also has a crack in the exact same location. Apparently that must be a common problem. Seems like every 69 exhaust manifold that I have seen for sale are all lh ones.
If that's true then I probably need to take a closer look at the RH manifold that I have. It sure looks like a crack to me, but it is in the exact same location as the rh manifold that you sent a picture of. Also, what appears to be a crack on my manifold is only on the outside part of the manifold and not on other side, just like the rh manifold that you have. Now you've got my curiousity going and I wonder if anyone else reading this thread can canfirm the same type of casting flaw on the rh exhaust manifold?