It was a modification, not a repair. I had to cut the flange off and rotate it to make more room under the hood. Here's the procedure I used:
Cut flange and thoroughly cleaned and beveled the area to be welded.
Placed manifold in the oven to preheat. Got it to 380 degrees.
Tig welded on AC with 3/32 thoriated tungsten at 175 amps.
Used Ni-99 filler.
Completed root pass and placed back in the oven for 30 minutes so it wouldn't cool too fast.
Completed another pass and placed in oven to cool for 4 hours. Oven off.
I hope it holds.