Is This Exhaust Manifold Repairable?

For my 33 straight eight, i would certainly try to have it repaired, cause there is basically no alternative. I know, ive got one that looks like it has been tried to repair about ten times, in ten different places. Lots and lots of cracks
For yours, you have to decide if originality is worth the effort (which may not be successful) and the expense.
If i had a repo on the shelf waiting? For me, the answer would be no.