I've had a cracked manifold (on a 51 dodge) welded successfully - nickle
rod - I would expect that a good welder could build up some material if you
needed it, and then some work with a file could bring it back down to level
enough for a gasket to seal.

FWIW, 99% nickle rod, while expensive, is real easy to run, even on
AC. Takes about half the amperage of 7014, sticks well, and files
easily. If it weren't so expensive, I'd be tempted to use it for
everything. They often sell it in hardware stores with just a few
rods in a package for $5 or so. Beats buying a whole pound for close
to $50...
--Glenn Lyford