Help - need to replace OMC exhaust manifold

[blaze68]

I am trying to find a good used exhaust manifold for a boat I just bought.

It is a 1989 2.3 litre OMC cobra. the one that is on there now has a lower crack and leaks a small drop out every second while its running.

Does anyone know where I can find a replacement or even a conversion for this?

Thanks for your time if you can help.