I'm new to engine building, but I research and learned alot. I love this stuff and know it's gonna be my career. I want to know how much can you bore a b18c1 without having to resleave it? And are you able to fix a detonated combustion chamber/head? This is what I mena by that:

Closer look

Help if u can

 

The research should have told you that you generally don't open your cylinders up more than 82mm before sleeving them.

Whether a head can or can't be fixed, largely depends on the machine shops and their experience and resources. Take the head to a few of those shops and see what they have to say about it.