1963 C10 Intake Manifold

[my63c10]

I blasted my intake manifold that was on my 230 motor from my '63 C10 and found a crack where the bolt goes to attach the exhaust manifold and gasket (see pics). As best I can see, the crack goes down about 3-4 threads and stops. I can put a bolt in and tighten it but I'm wondering if this will be a problem down the road.

Does anyone know where I can get one of these? It is GM part/casting # 3822918. From what I can tell, they don't cast these anymore. I've found other ones but mine has the hole on top for a rod to go through for my throttle linkage (see pic).

Should I just use it as it may not be a problem?

Thanks!