Is this the end of my V20?

[djfam]

So I finally got to check my compression and it is pretty good. 140, 110, 125, 130. I'm a little concerned about the 110, but it is still right around the right margin. I am still diagnosing the issue, but I am not so sure now that I have a cracked block. There may still be a head gasket issue, but I am leaning now towards the exhaust manifold and elbow as culprits. If the water back flowed through the manifold into the engine, through a crack or busted gasket, I think this may have caused my issue. I will check this weekend if time/weather permits.

One problem I will have if it is the manifold is that it is not made anymore and not really able to be purchased anywhere. Mercruiser number is 71527A17. No-one makes them so I guess I will have to buy used on Ebay if anyone ever posts one. Can I take these to a machine shop for repairing?