My beautiful Spanish Lover Blue Belle ('76 450SL) seems to have something like a crack near the flange on the right side exhaust manifold. I changed the exhaust recently and it's not loose, but what kind of fun am I looking at to get the manifold off

? I can't see how I would possibly remove the lower bolts. I can't even see where they are.
Anyone ever heard of a crack around here before and know if it's weldable? My year has the cats in the manifolds
Any words of wisdom before I jump in?
I did the Waterpump etc and the rest of the exhaust and about a 100 other things on her, but feel I need to fix this to sell it. It sounded so good before - then one day it developed this sound. I assumed a flange leak, but it isn't.
Thanks
RZ Rob