Yup its nasty. Imagine how badly it runs

I found a jackpot of '85 manifolds on car-part.com averaging $30,
and a nice guy on S10 forum has offered to send me one.

 

Getting a different one seems to be the way to go...that is a big crack.

Brazing is similar to welding but is more like soldering. You would use an oxyacetylene torch and brazing rod along with a flux, to fill in the crack. I have a little experience with it, enough to know that its not something you could just pick up right away. A weldor who is good with an oxy torch would probably do it if it wasnt such a big crack. It's done a lot on farm equipment where money may be tight, plus the cost of a tractor exhaust manifold would be rediculous compared to most automotive manifolds